I don't want you to die. I don't want you feel pain anymore either. I think that it will get better, it's just going to be really crap for a while first. I think you are so strong to have survived three years feeling like crap. Good on you for surviving.
I'm sorry to hear that you aren't feeling better yet. I'm sorry to hear that the doctors and physiatrists don't seem to really be understanding how you feel. It must suck that your counsellor isn't helping either. I hope you can tell them that, tell them how you feel. Maybe even tell that science teacher? It's nice to hear that he is taking care of you.
Next time you don't think you can make it through the night, how about you do your favourite hobby? Watch a movie, read a book. Do whatever you enjoy.
No matter the time there are people you can call, and I want you to,
There's life line 13 11 14
suicide call back 1300 659 467
and kids help line 1800 55 1800
They are awake 24/7 and they want to talk to you! I don't think anyone can understand exactly how you feel, but these people will try.