Why am I always so lazy?

Ok so I've been lazy my whole life but since I'm 15 now, it's been worrying my mom so she took me to the doctor, he said it could be what I'm eating and yeah I used to eat junk food so I stopped eating it for like 3 months now and I've gotten much skinnier but I'm still lazy so I revisited him again and he told me to take these tablets called Super B-Complex and it's supposed to help convert the food I eat into energy and it still doesn't work, I've been thinking of just giving up and just take some adderal since it gets you hyper. So is there anything I can do other than take adderal???