Do remember- it really is trying to help. Negative self talk really is a useful social animal trait that's just going a bit haywire, so figure out what its trying to do and be nice to it.

Also, pain can be experienced first as emotional distress, especially if its pain you've lived with for a long time, and its just hurting extra bad.

Sometimes its easier to do self-care when you picture it as outside of yourself.
So when you're really feeling like shit, try acknowledging its concerns, rational or irrational, and then tell your little red cat its doing a good job and its safe to take a nap.

It isn't a magic fix, but its an actual process to go through. And that feels better than just stewing.