How to cope with test stress?

My school is very academic and we get tested every month, the thing is they test every subject in 5 days instead of spreading it out.

Every month we have to learn every topic we’ve done for each subject so you can imagine, it gets worse every month as you start learning more.

I’m so unbelievably stressed, I have so much this week and I usually get everything above 90% but I’ve completely given up. I didn’t revise properly, I can’t do it any longer. My mental health is suffering greatly and I need to find a way to cope fast.