Sounds to me like you've just hit a rough patch. I'm not really sure what to tell you since I have no answers myself. Though I do remember a post you made where you told me you were okay with who you are. You are no longer trying to shape yourself to fit others' expectations (thread here:
https://socialphobiaworld.com/threads/healthy-unhealthy-ways-of-coping.65895/#post-878089). You also mentioned times where you have slip-ups in that very same thread. I think this is probably one of those slip-ups.
Another thought has occurred to me, and I'm probably just projecting... but perhaps that heartache you feel is a longing for belonging? Maybe you're tired of being the odd man out, the square peg in a world full of round holes, even if you are completely OK with yourself. You might be feeling alienated. We are a social, communal species, and being on the outside can be draining.
But once again, I maintain that perhaps this is just a rough patch.