What Is Wrong With Me... Anxiety?

Ok, Im a 13 year old girl who is underweight (I'm 76 pounds and have been that since around last year, and I'm going into 8th grade), and I am usually stressed, I feel ike fainting sometimes, and I am always afraid, I get out of breath all the time, and some times i feel like I'm burning, I really just want answers, if I were to put my hands over my head, and pull up my hair, my arms get weak, and i cant breath, if my mom and I get in a fight, i don't cry, but I am depressed all day, I normally cant go to sleep, in fact, i stayed up till one a.m. and i was trying to sleep since eight p.m. ... I don't know what's wrong, I used to hang out with my friends day, and night, but I cant seem to get my self out the door, Im to lazy, too... And Im always fussy... (I'm also afraid of what people think of me) and I feel like rebelling against the world...I have a dirty room so i know its not O.C.D... If you have any thoughts, please ...TELL ME!