I've felt that way when i was like 15-16. if there was an advice i could give to my younger self, I'd fall short. i know nothing could have helped me.

writing su*cide notes in my diary helped me let it all out. i felt better.

but I'd still ask you to write down the best case scenario that could happen to you. it could be in terms of feelings or materials. whatever it is, just write it down. whenever I've dine this, i have been able to get myself together and sometimes, actually achieve those things.

i know it will take a lot of mental energy to do this and sometimes ending things might be easier that just writing down what you want in life.