The first step to cope with stress is to accept the fact that you are going through some sort of crisis. Whether it is school related or not, acknowledging that something bad is happening to you is the first step. Stop denying it and mentally programming yourself that everything is alright, because eventually, you will explode. In order to avoid this sudden outburst from happening, negation is something that needs to end right away.
After accepting the fact and not denying it anymore, ask yourself if this “thing” is worth making you experience your current crisis . Ask yourself, can it be fixed? Are there other solutions/alternatives? And if the answer is yes for any of these two, instead of sitting around overthinking about the problem, work on ways to approach it instead of avoiding it. Now, if it is too much to take, it is alright to take a break. Whether it takes you two days, one week, or fifteen days it is okay, as long as you put a limit to your break. The time for you to deal with the thing bothering you will eventually come around. Therefore, it is better to attack the problem with a clear and open mind, than with one cluttered with worries and negative thoughts.