Burnout affecting relationship

Hey all, I just need to vent a little.

I've been trying to manage school full-time (15 credit hours), part-time work (about 20 hrs/week), job searching, outside projects for experience, a relationship, volunteering at church (piano, choir, food prep, etc), and I realized I will need to take classes in the summer as well, with no break beforehand. I'm just so burned out. Part of me doesn't want to say that, because I'm managing to keep deadlines and commitments, but I have less and less energy. I've taken a couple quizzes on health sites to get a better idea, and they both said I'm very burned out and need to do something about it asap. I just don't see it getting any easier anytime soon.

I feel like it is affecting my relationship a lot because I'm frequently in a state of anxiety and worry, I find myself being very critical about little things (like if he didn't say good morning or didn't say what I wanted when I needed support). I feel really bad about it and I don't at all want to be a crazy or mean girlfriend, but I just feel like he doesn't understand what I'm going through. I feel like cutting back my schedule would be lazy, and I sometimes feel that anyone less busy than me is lazy. But it seems I am doing too much.

I guess I just really want to have a healthy relationship and not sabotage it by being negative and stressed and exhausted all of the time.

Thank you for reading <3