Setbacks come here, too. We're entitled, Traic. Don't beat yourself up but get back up when you can and think of all the progress you've made.
Sometimes the pain makes it hard to see how hard we've come, but it's there, nonetheless.
One thing that helped me, FWIW, is to tell myself repeatedly about "today".
"Today", I am ok. "Today", Perv is not important.
"Today", I did all these things and I made a list of all the stuff I did on my own. I look back at it at night when I'm down and it helps every time.
Making "today" a present tense time helps reel our brains back into the now. This was a tool that an IC gave me and it helped during some pretty dark days.
A person is a person, no matter how small. -Dr. Suess
Perserverance and spirit have done wonders in all ages.