Feeling extremely overwhelmed with my rabbit right now

I've had my rabbit for almost two years. He was a shelter rabbit and an adult and neutered when I got him. He'd always been perfectly behaved, calm, non destructive, perfect litter habits, I got insanely lucky with him.

I'm going through a pretty stressful time at the moment, I just moved back to my home town, I'm taking care of an ill family member, am currently working and looking for a second job, and will soon be starting a class. My bun has decided this is the perfect time to stop being perfectly litter trained, and has started peeing and leaving poops outside of his litter box. I've tried moving the box to where he's been peeing most, which only halfway worked. He'll use it but it hadn't stopped him going outside of it entirely. I have tried enticing him with hay, offering multiple litter boxes, nothing has fixed it. I don't know what caused it and don't know how to fix it.

With everything else going on right now I just can't handle this and am starting to get really overwhelmed with his care. Every time I think of needing to do his care I almost feel like crying. I feel bad for being upset and overwhelmed by him, but I just don't know what to do.