In order to understand where to start, you need to highlight the most important and urgent things and begin to implement your plans with them. At first, written assignments should be made and then oral, we must begin with easy assignments, gradually complicating them.
At one time you should work on tasks, let it be an hour or two, the rest of the time you can rest. This will not allow you to overwork and help not to discourage the desire to learn. A habit will be worked out and tasks will become easier.
And preferably you should rest in the fresh air. Be sure to take breaks. The change of physical and mental activity will help you switch, tune in to the positive and gain strength.
At some point you will understand that this snowball will not stop. And so, it did not crush you, do things on time. This is the case when it is easier to prevent the situation.