I use to be like you at the same age, and my problem was:
1. I started to smoke cigs at VERY young age(11 years old) I was 18 when i finished the high school, I quiet smoking at 20 now I'm 25(best decissiion in my life... to quiet smoking)
2. Working too much at computer(I'm a coder, I start to learn to code at 14-15) I still have a job in 'coding' community, not a genius coder but I can handle even complicated task(I love what I do).
3. My sex life was somtimes worst sometimes very good in high school(AAaa yeah I losed my virginity same like starting cigs, very early and I can't believe I talk about that in public but hey maybe it will help u and that's matter). Even right now I don't have a gf but that doesn't meen I don't have a great sex life, I live in a poor country where girls are looking for money and to be a doggy for them and I know that so ... I don't sleep with girls which are involed in a relationship or married womens, I'm just looking for the girls which are looking for the same thing I'm looking... plus I don't have time for a bullshit things like 'love' ... where I live 'love' means money.
4. Try to eat more natural u can, if u eat fast food, stop, if u eat MC Donalds, stop, and so on... I'm 90% vegetarion from 20 and this is another best decission in my life) That's don't means it will work for u maybe u will feel better if u eat MC Donalds... who knows? Human body is an amazing machine.
5. If u don't do a sport, pick one, like I say human body is amazing... 5000 years ago we run and hunt animals right? U need to move your hands and your legs everyday, jogging,tennins I don't know just pick one! I run almost every day on the beach 10-15km from 20, try that... the girls are looking for guys which do a sport(see what I say at 3.
)
6. Stop watching porn if u do that.
7. Try to sleep 6 and MAYBE 7 h per night, at your age u don't need more, very important, if u sleep 10 that's hanneping u feel tiered.
8. Stop be a naive, people these days are bad and if u trust them too much is it possible to f**k u when u even don't expected.
9. Don't ask god for help because there is not anybody in the sky, u are on your one.
10. Don't go to any doctor and don't take any pills for depression or whatever I do that and any of them fix my 'depression problem' or my 'tiered problem' whatever.
11. Don't worry to much what you will gona do in life, do what u love and if u work hard u will not fail and is much better than any other shitty job which society offer to you, Society is build by humans, and humans are hungy. The socity institutions don't care about u, they want to make u a retard if is possible and to work for them(shitty jobs).
I hope it will help u, don't go to any doctors unless you maybe suffer from something and u don't know but u have a little depression and if u go to them they will put pills in your mounth. Don't take my advices as good, maybe for u will not work but maybe will help u even a little and that all that matters.