Very good. I like it

I love it luv, keep going! I think I know who you're talking about, but while I know a lot about you, I don't know eveything. I love you lots, and see you soon, then maybe I can make you tell me ;D

I think this is written pretty well, but to be truly honest it's hampered severely by the sheer amount of grammatical and capitalization errors. I normally just list off what needs changing based on where the error is, but it's almost easier to rewrite the poem to show you (if you're legitimately unaware) of how many there were/are.

Please don't consider this offensive, just a note on how to improve your writing!

There were lots of apostrophe errors indicating faulty possession.

-

"Mind blowing how a person can change so quickly
Amazing he even noticed my nice doings
I wish he couldn't see my heart in my eyes
Because I can't contain what I think

All my life I've been pushed aside
Unnoticed and outcast
I made myself noticeable
I made them realize who they're dealing with

I cower from the smarter
I strive to be everything yet nothing at all
I wear these clothes but they aren't mine
Did he recognize it?

Symptoms drive me crazy
Do they even exist?
No way can he love me
I am a source of pain and and loss for him
Love never finds the way

Many days have passed in wanting
I don't want what I now have
Could I be this greedy
He's right there but I'm scared

Hatred and nothingness consume
Images block my mind
Fuzziness fills in the place of vanishing brain cells
Drifting into madness I have one thought
Him and her
But never me"

3/5.

Also, the title should be capitalized and have an apostrophe as well!

"I'm not that girl" (period optional depending on your style, but from a general syntax point of view - it should contain one as well after girl.)