I've been having the same issue. Talked to my therapist about it today and we figured out I got triggered by something innocuous, and then we worked out how to deal with that by talking back to the thoughts and where they come from. It was really helpful.

I thought it was my meds but she didn't think so. I have a diagnosis of major recurring depression and PTSD and right now the PTSD has been flaring after many years in remission. It happens, but she's been really helpful. My experience is that it's a pain but it can be managed.

Hang in there. I hope you have a therapist and a shrink or can get one. They can both help with this kind of thing in a major way.