This is a very interesting idea. But like the girls said before me you have some standard issues you need to work through. You repeat your self a bunch, (why she was like that for two weeks.) also the grammar and spelling too. You could really benefit from the guidance from a beta. WOrk on those and you will do wonderful!

Noticed you made a lot of the same mistakes that most new writers make.  Nothing to be ashamed of, just thought I would point them out.  Most of which are real easy to fix.  Watch for grammer, puncuation and tenses.  Break down some of your run on sentences with either commas or make them into two sentences.

Example for run on: This may sound strange but there are vampires out there that don't even know that they are we call them the unknown.

Option 1: This may sound strange, but there are vampires out there that don't even know that they are, we call them the unknown.

Option 2: This may sound strange, but there are vampires out there that don't even know that they are.  We call them the unknown.

Example for puncuation/grammar: This mood of hers has been going on for two weeks now her birthday is only two days away, what is causing her to act like this thought her mother.

Option: This mood of hers has been going on for two weeks now and her birthday is only two days away.  What is causing her to act like this? thought her mother.

And make sure your italics for thought have gone through, they are not showing up in the story.

Example for puncuation/grammar 2: "Where this letter comes from and how this S person knows my name," she said.

Option: "Where does this letter come from and how does this 'S' person know my name?" she wondered.

Make sure you don't skip words such as 'does' from that sentence.  Also make sure you use '?' when it's a question.  Easy way to remember this is if the sentence starts with 'who, what, when, why or how' it's a question. 

Make sure if you have larger paragraphs that you break them up a little.  Makes it a lot easier to read on a computer.  If it's the same person talking, you can try starting the next paragraph with ".  Or after they have finished a sentence if it is not all diaolog.  Also, never have more than one person speaking in the same paragraph.

Example: "I am glad you came," said the voice. Kagome looked to her left and saw a man standing there. He was wearing a simple black suit with a red tie also a long black trench coat. Kagome could not believe what she saw this man can be human he has golden eyes, long silver hair which was tied in a low ponytail, two purple stripes on each cheek, and a blue crescent moon on his forehead. The man walked toward Kagome and sat down next to her. "My name is Sesshoumaru and I am a vampire," he said. Kagome gasped she could not believe what she just herd this man comes up to her and tells her that he is a vampire. She felt like running away but for some reason she couldn't. "Let me tell you some things about vampires we are just like everybody else except we drink blood instead of eating, he told her. Sunlight, garlic, holy water, and crosses can not kill us. Also we don't hunt humans for there blood we have a special place to get our blood. Well let me cut to the chase I call you here to tell you that you are a vampire," said Sesshoumaru. "I am a vampire, how can this be I don't crave human blood or have any special powers," said Kagome. "You are what we call an unknown which means you powers will not fully awaken until you 18th birthday that is why you are feeling this way your powers are awaking. I am here to offer a deal with you I want to help you with your powers and train you how to use them," said Sesshoumaru. "How can I do this I have school," said Kagome. "This won't be a problem the training only happens at night, said Sesshoumaru. Kagome was excited so I not really human she thought. "Ok I accept you deal Shesshoumaru-sama," she said with a wide smile. "Good you will come by my place in two days and your training will begin," said Sesshoumaru and he pulled out a card which was red with gold lettering stated.

Option: "I am glad you came," said the voice. Kagome looked to her left and saw a man standing there. He was wearing a simple black suit with a red tie also a long black trench coat. Kagome could not believe what she saw this man can be human he has golden eyes, long silver hair which was tied in a low ponytail, two purple stripes on each cheek, and a blue crescent moon on his forehead. The man walked toward Kagome and sat down next to her. "My name is Sesshoumaru and I am a vampire," he said.

Kagome gasped she could not believe what she just herd this man comes up to her and tells her that he is a vampire. She felt like running away but for some reason she couldn't. "Let me tell you some things about vampires we are just like everybody else except we drink blood instead of eating, he told her. Sunlight, garlic, holy water, and crosses can not kill us. Also we don't hunt humans for there blood we have a special place to get our blood. Well let me cut to the chase I call you here to tell you that you are a vampire," said Sesshoumaru.

"I am a vampire, how can this be I don't crave human blood or have any special powers," said Kagome.

"You are what we call an unknown which means you powers will not fully awaken until you 18th birthday that is why you are feeling this way your powers are awaking. I am here to offer a deal with you I want to help you with your powers and train you how to use them," said Sesshoumaru.

"How can I do this I have school," said Kagome.

"This won't be a problem the training only happens at night, said Sesshoumaru

Kagome was excited so I not really human she thought. "Ok I accept you deal Shesshoumaru-sama," she said with a wide smile.

"Good you will come by my place in two days and your training will begin," said Sesshoumaru and he pulled out a card which was red with gold lettering stated.

See how much easier it is to read?  Last two things to go over since this review is getting longer than I meant to lol.  Tenses and detail flow.  First tenses...

Example: Kagome walked to her room tosses her backpack aside and lay on her bed.

You go back and forth between past and present and it makes the sentence difficult to read.

Option: Kagome walked into her room, tossed her backpack aside and laid down on her bed.

And detail flow...how well the words/sentences/storyline flow in together.  Using someone's name or a pronoun such as 'he or she' at the start of most sentences interrupts the flow.  Try starting with an action word.

Example: He waved his right hand and a red envelope appeared on Kagome's desk. As fast the figure appeared it disappeared just as fast. Kagome sat up she felt like someone was watching her she looked at her window and no one was there. She saw the red envelope on her desk; she got up from her bed and walked over to her desk. On the red envelope her name was in gold lettering. She picks up the envelope and sees on the back there was an S seal. "Where this letter comes from and how this S person knows my name," she said. Kagome opens the envelope and remove the letter; the letter was also on red paper with gold letters.

Not going to rewrite all of it, just give you the general idea of what to go for.

Option: Waving his right hand, a red envelope...Sitting up, Kagome felt like someone was watching her...Picking up the envelope, Kagome saw, on the back, an S seal...

You don't need to do this for every sentence as that would cause the same problem as before, but try and mix them up a bit so it doesn't end up sounding like...He walked into the room.  She looked over at him.  He nodded his head to her.  She went back to reading her book...type thing.

I agree with inu_tiger. Work on those and you could have a really good story going.