i am 15 years old and im interested in taking adderal but i'm not...

i am 15 years old and im interested in taking adderal but i'm not sure if i should. I wasn't diagnosed with ADD/ADHD, its just that i heard about this medication and thought it be a good idea to try it because i feel that i need to be more focus in school, im often tired and don't really feel like doing homework...i have to change that, and i feel like adderal is the only way. I also heard that while taking this medication you start losing weight because it decreases your apetite, thats not a good thing for me because i only weight 105 do to having a very high metabolism, so i really can't afford to loose any weight if anything im trying to get to at least 120. So do to this concernes im not sure if adderal is for me; however i need something that will help me get better in school. What do i do?