Sara - I don't know if any of the following will help. But I had a visceral reaction to what you just wrote on a number of levels, it seemed like clicking "like" wasn't a very honest action. So apologies in advance if this doesn't resonate in return.
The loss of self-esteem when the one or ones who have fueled that very part of your identity are no longer in your life — well it isn't something I've seen or dealt with from the romantic-side, but very much from the professional. I've seen it happen to coaches especially, very successful coaches whose careers ended prematurely (they ALL think their careers end prematurely)... and when your job involves going to work where people are literally cheering for you (or booing at you, which, trust me, is a form a cheering, self-esteem-wise) it is hard to take. They ask what good are they?
I felt/feel it too, when I had to stop working because of my medical issues. It's hard to describe to someone what it's like to walk into a big arena and tens of thousands of people have paid to be there to see something you're part of. To be walking around down in the center of it... and sometimes with friends and family in the stands. It's quite a thing, and it fuels you. And when it's gone, you start saying ... well, without this, what is my value?
There aren't easy answers to it. As you said, you look for evidence to reinforce this. Once you're out of the loop, people aren't returning phone calls like they once did. I definitely let unreturned messages bother me much more than I ever did before. But I try to work on all that.
But you also try to close your circle. Replacing the source of self-esteem with another is just a band-aid. People try to do it, but it's not enough. But it's also ok to look at what REMAINS and realize it's enough. Look at that people in your life who valued you before and after, and appreciate them more. Yes, there's some guilt that maybe you should have appreciated them more earlier... but changing the past is not worth anyone's time or effort.
I am not going to tell you that you have lots of people here who think you're the bees knees (present company included), because as mentioned, that's a band-aid. But I know there are friends and family in your life who think you're pretty great... and they're the ones who you can lean on if you need a bit of a self-esteem boost. But as you're doing, the rest comes from self-explorations and deciding that you rely on yourself.
I know you know all this. I almost deleted the last paragraph because it's SOO on the nose... but eh, it's already typed and I feel a bit lazy this afternoon.
Wish I could offer any pearls of wisdom on the guilt stuff. If you happen to figure that one out, please share. I'm still working on that myself. Miles to go before I sleep.
Love,
Allie