I'm 17 I am not prescribed but I use to take it to help me focus....

I'm 17 I am not prescribed but I use to take it to help me focus. I moved with my mom and stop taking all of Adderall. I couldn't seem to focus everything distracted me. I bought some of a kid for 2$ each got 10. Bout 30 minutes of taking it I felt great and got everything done. Took 1 20 mg every day for the 10 that I had bought. dropped weight rapidly. about 7 pounds in like 3 days. couldn't seem to eat. Now my heart is pounding. I m afraid to get prescribed but I really need it. My grades went up tremendously. but when it wears off I feel pissed, and extremely tired. It also helps within people. I seem not to give a *** and I have a pretty good day. Right now tho I don't seem to feel that it is working. I'm also trying to lose some lbs ne ways for weight competitions and it helps but I am not trying to lose muscle. I just don't remember any of these symptoms when I was on it in 9th and now I am a senior? My side effects: jittery mood swings cant seem to be still very focused cannot sleep at all * does it speed your metabolism up? and will it hurt my heart?