You’ve already had several good suggestions here.

I learned that when rest no longer leads to recovery, that is burnout and maybe even depression. Pay attention to this feeling and take it seriously. Good luck.

If you’re thinking about what you could be doing, you might have some unhelpful conditioning related to “being productive” and other such myths of how to live “correctly”. You might be able to think your way out of that way of being and you might need to talk to someone to do this, such as a therapist.

If you’re worried about forgetting something that you need to do later or about some deadline sneaking up on you, then writing things down and setting reminders could help. I did a lot of this and it trained me to literally forget things that I didn’t yet need to start working on without risking missing deadlines. I found it very freeing. Something like that might help you.

I hope you find some peace from something in these replies.