I fall into this trap all the time. I feel good now, so I must have been exaggerating how bad things were back in February. I'm getting plenty of stable sleep now, so all of those episodes where I didn't sleep more than 2 or 3 hours a night for a week? Clearly just anomalies, they won't happen again.

Except they do. And I'm trying to wise up. I'm in therapy "for real" this time, so hopefully it will help. I can't figure out any other way forward, because everything I've tried on my own has failed. So for me, it's time for help. It kinda sounds like you might benefit from some assistance as well. Maybe there are some options you haven't tried yet?

BTW, not all PhDs fall into the smarter-than-thou category. Some of us are struggling right alongside everyone else here. (though I'll be ABD for at least few more months...)

Hang in there - I've seen you make some really insightful comments, and I hope you can both find some support for yourself and continue to keep supporting others.