lost I'm so glad you are getting help. Please don't blame yourself for letting things go on for too long. You are very young, people much older than you don't know how/haven't got the energy to seek help, then how should you.
Really hope your parents are starting to be supportive.
Hang in there, things may be sh.., but you are doing something, getting help. If you get ads it takes time for them to work, but they do.
Re. School and exams, I know everybody is pressurizing to get through, finish the year, moving forward. But you know, you are not very far in the educational system, there is always a solution. Doing exams later on, waiting for you to feel better. Being depressed, takes your mind of everything, but it also affects your memory and does so for quite a while. Talk to those who are accessing your, your gp, school about how to go about this.
My ds didn't attend his university classes for several months, he simply couldn't. But guess what, when he started feeling better, he returned and he is up to speed and has finalized his master.
You can do this, you have years ahead of you to take those darn exams, if it doesn't work right now.
Best wishes and strenght to you.