When my sitch was at its worst, I struggled with anxiety on Friday afternoons. It was odd, and I had a hard time figuring it out, but is was consistent. Eventually I realized it was that weekends had been, prior to OW, great family time for us and I used to always look forward to the weekends. Once OW was in H's life, I never knew what to expect, and I spent many Friday nights alone because my kids are teenagers and would be with friends and H would be AWOL with some flimsy reason or another. It was torture.
Anyway, good job on working through the anxiety throughout the day today, it often is a bit of a "mind over matter" thing, and talking yourself through it helps, as well as breathing. Also, good to hear you are buying yourself some new clothes! W will be in for a pleasant surprise!
I'm sure you will think of a reason your day was great. Just take some good things and expand on them a bit.
I also relate to your struggle about missing your W, the conversations, the contact etc. I struggled so much with that. It was like there was just this gaping hole that had been filled by my H, my best friend, all those years and it was just suddenly ripped away from me. I tried to do what is suggested here and fill that with other things, friends, GAL, the kids etc. and that DOES help. Sometimes you just have to accept the reality, like any other loss, that it is just gonna hurt. But, if you can keep doing what you are doing, you are more likely to have your W back in your life even better than before. And,if that doesn't happen, it is good for you to make these changes for yourself no matter what.