I'll tell you what I would do in your situation based on my personal experience
1. Get rid of any blades, rope, anything you can use to harm yourself
2. Talk to your friends, parents, anyone you trust about what you're going through
3. Get as much sleep as possible. I always had trouble sleeping, which greatly contributed to my deteriorating mental health. Once I got some sleep, my mental health drastically improved.
4. If school is one of the biggest things affecting you, skip school. Take a personal day out on the town. Grab a coffee, take a walk. Your mental health is more important than algebra.
5. Find a hobby. You're already doing that with Imgflip, and burning up that leaderboard I might add! Just have something to keep your mind occupied.
Those are the tips that worked for me, hopefully you can push through the darkness because there really is a light at the end of the tunnel.