Happy birthday dude. I thought I loved yoga - bikram for four days is nuts !!
I know what you mean about friends - I realised post BD that I had focused so much on my children and family that I had a lot of acquaintances, but only a handful of good friends (and even they lived an hour or so away). Man, the void H left was huge and when he started to have the kids over so much, the sheer emptiness of it was overwhelming. But, I made new friends and I learned to enjoy my own company.
We all have setbacks, running into them when they are obvs. on a date, our first birthday without them, but we get through it, because we have no choice. You are doing great. TBH I think in many ways we are getting through it better than our spouses. We face the fear head on. We accept the loneliness. We allow ourselves to feel the emotion. We deal with it in healthy ways. I never would have known how strong I was until I had to pick myself up off the floor and put myself back together. Our spouses don’t even know they are broken
