I hate how much I sleep

I am constantly tired and lethargic, no matter how many hours of sleep I get I always feel like I haven’t slept in days. So whenever I get home from school, I always end up taking like 3-5 hour naps, stay up for an hour or two, then go back to bed until I wake up for school tomorrow. I feel like I always miss out on so much because I’m just always sleeping and tired. Whenever I talked to my doctor she just put me on vitamin D supplements. I’m still just as tired and I don’t know what’s wrong. And when I do see people, and manage to stay up, I’m so lethargic and tired the whole time so I can’t even really enjoy it. I hate this so much. No matter if I nap or not, no matter how much I sleep, I’m just always so fucking tired and it’s terrible.