One thing I like to do is to write down literally anything that you have to do. Get down to the root of your problems by seeing what activities, homework, etc. may be causing you stress. At some point, stress will be there and you will have to deal with it. It all depends on the mindset you have and I know how overwhelming it can get.
Find a distraction or a interest you have such as playing outside or doing some meditation. Whatever works for you best. Listening to calm music, coding, and hanging out with people are a few things I like to do to unwind.
Good luck!