please someone help!

I think the best thing Ты can do is try telling your parents to lower their voices down a notch. If that doesn't help than try going to someone's house for a while to do it- like on of your friend's.

If it's the kind of stress that turns into anger then try screaming into a подушка and just laying there for a bit. If its not that kind of stress then try finding something that Ты like the smell of like a scented candle. And if it's not too hot then Ты can заворачивать, обертывание yourself in a fluffy blanket.

just do something that is calming, like sleeping или reading.

или if youre Храбрая сердцем enough go downstairs and tell your parents that their fighting is stressing Ты out, and see if that solves the problem

Try Письмо about it. It usually helps me.
It works better if Ты make it out to be a letter to someone who is stressing Ты out the most (In this case, it's your parents and teachers) describing how you're currently feeling.
Don't worry, Ты don't really have to give it to them though... It's just an amazing way of venting for me.

I feel your pain, it happens. Honestly, I would Переместить outside или to another room just to focus. There isn't much that Ты can do with fighting parents, but homework can be done in no time.