I crashed hard yesterday for the first time since I moved out

I have ongoing anxiety problems. They've reduced immensely since I moved out, and overall I've generally been feeling good about myself. On Thursday afternoon I started getting bogged down in my work, with a kind of brain fog, I've experienced that a few times in the past when under pressure. It impacts my ability to problem solve, and as a result I couldn't work properly on Thursday afternoon. A colleague of mine was also stuck (for whatever reason) and we agreed to work on both our problems together on Friday. However, he posted a fix for his problem at 7pm on Thursday evening, I had an anxiety attack as a result, feeling inadequacy I suppose due my inability to work properly. I vowed to start work early on Friday and make up for lost time. I was about half an hour into work and I was just hit with this immense wave of grief, for want of a better word. Initially I thought it was related to my inability to do my work. But now I'm wondering have I got it backwards maybe? Are these emotional waves creeping up on me and I'm latching that feeling onto my inability to work, when in fact it's the opposite way around, these feelings are creeping up on my and reducing my ability to work, if that makes sense. In any case, it hit me hard. I messaged my boss and told him I couldn't work (because of a wave of grief) and needed the time off as I wouldn't get anything productive done anyway. So Friday morning I just watched some tv, tried to play some games without success, I went for a walk, then I just crashed completely. went to bed and stayed there for 5 hours, in a half sleep half awake kind of state. This is the first time this has happened in this context, this severely at least. It's been over a month since I moved out, and over 6 since we signed divorce papers. Anyone else experienced anything like this?