All I can say is that I've been in that exact place many times. Sometimes, it lasts for months, sometimes weeks. Doesn't seem to matter whether I'm on meds or not - it has happened in both cases. It can be very difficult, to the say the least, to get out of that cycle.

But, if it gives you any sense of hope, I've come out if for periods of time, just like I've fallen into it. I find that if I'm gentle with myself (don't let the intrusive, ruminating thoughts in my brain consume me), allow it to "run its course," and accept that it's part of my existence now (at times), I can cycle out of it more quickly. If I let my brain run the show, "you suck, you're lazy, there's no hope, this is how it will be forever," it takes longer for that way of being to pass.

I hope this passes quickly for you. There IS hope!!