You're probably just burned out. Intense focus for long periods of time tends to do that. Take a break; focus on maintenance for a while. You will bounce back

Well I have been in the same condition, I procrastinated as much as I can and I was trying to runaway from all the responsibilities (I resign from my job and didn’t continue my study) but that’s not good. I get more stressed and blamed myself even the condition itself. I realize it’s not healthy, and what I’ve been doing is wrong. So I tried to do my best for what I was doing that time. And fortunately I got opportunity to continue my study, and the job I’m doing now is kinda fine, I mean it’s a job. Just take a breath first, idk my story maybe won’t help you, but I hope all the best for you :)

Have you been tested for cv19?
you may have a mild dose... Fatigue is one of the symptoms