Oh, I understand you so much. I'm in a similar situation now. I have a lot of courses, and I also became a member or the student council, which takes a lot of time. And I just don't have enough resources for all those things. I don't have enough time or power, and because my grades are worse now, I don't have motivation.
But it's life; things like this happen, and it's certainly possible to improve the situation. This weekend I'll just do nothing and spend days doing something I like to get rest and reduce stress, and from Monday, I'm starting to do everything possible to get better with my studies.
And I wish you luck and strength to overcome all your difficulties.