I think this story has a lot of potential. And the plot seems rather creative, too. But, I may have to give you a few critiques. And just so you know, I'm not trying to be a bitch or anything.
Well, first of all, punctuation is always a first. Along with capitalization. And grammar is always a must. The lack of these things sort of threw me off and made me not really want to read anymore. In fact, the way you expressed your words was boring and it was a struggle to get all the way through.
To capture and keep the reader's attention, you have to spice things up a bit. Try using more descriptions along with metaphors and similes. Oh, and try to think of more adjectives instead of just saying one word over and over again. Readers will get bored and think the story is cliche.
Another thing that you should consider changing is calling Mercy's best friend 'emo'. It will throw people off and you may loose readers for the fact that you just stated a major stereotype that people dislike. Emo is a music genre, not a person. And some people feel strongly about that subject. And you shouldn't say 'gay', so people won't take offense. Like, when Martin said something in a gay way or when Mercy started to dance around the fridge in a gay way. Some people may think you are classifying homosexuals as being foolsih and stupid. And they aren't. That would be another stereotype. Try saying it like, 'He said in a girly way' or 'She danced in a foolish way'.
You should also think of putting more emotion in Mercy's perspective. Her parents had died, and the way you portray your character, it seems like she is indifferent about the situation. For example, when she was IMing her best friend she just simply stated, 'My parents died. Now I'm adopted'- Or however you wrote it. Also, in the beginning, you should put more feeling into the text. If my parents were killed and I was suddenly adopted, I would probably have a heaping plate full of mixed emotions. Maybe you could go back into Mercy's childhood and pull up some memories of her parents. It would really stir up emotions for Mercy and it would gain more interest for the story to the reader. There was one quote though, that I absolutely adored. It was, "And its true because I now instead of waking up every morning wondering what my mom is making for breakfast I wake up wondering when the nightmares I keep having are going to end."
And you should always use quotation marks. I had a difficult time getting through the chapter because of the lack of punctuation. Take these things into consideration, and maybe try to improve this story. I think it has a whole lot of potential, and it seems quite enjoyable to read. =D
Update soon, love.