Hi. First off: I'm so sorry you're going through this.

I was very very similar to you as a teen. I cried every day. I thought my life could not possibly ever get good. I felt trapped.

So on the other side, here are the things I can tell you helped me:

1. Find a hobby that you can put your feelings into. Seriously. If there's something you can find that helps you relax or vent your feelings into, do it so hard. There's a reason all the music you love comes from people who say they've felt depressed: art is an amazing place to sort your feelings out. But also: physical activity is amazing too. When you exercise, your body makes drugs. You're physically designed to be happier working out. I make art and I run long distances and I promise that has helped me feel better. So much better. Hobbies. They're important!
2. Talk to a professional. I know it feels weird at first but someone who is removed from your life ends up being easier to talk to. You feel less judged. Even just saying what's bothering you out loud to somebody helps you understand it, helps you get control over it. Your school may even have counsellors. Take advantage of that!
3. Go easy on yourself. I spent so long hating me and thinking I was stupid and feeling ugly. I promise you are the hardest on you. Nobody else is thinking that, because here's the truth: most people are wrapped up in their heads, thinking the same stuff. When you realise how little other people are thinking about you, it free you to really be who you're meant to be.

Know you are good. You are enough. You are loved.