I feel like I should be doing more, but am I doing too much right now? (see details)?

People have different levels of stress tolerance. If you are already feeling stressed or close to your breaking point, I would say not to add anything else to yourself. If you feel capable, go for it, add things one thing at a time. If it becomes too much to handle, start lessening your load. Also, I'm sure you have plenty of time to do all of that stuff when you get done doing school. Good luck.