Hi Lemonbar,
Do you like animals? If so, you might want to consider getting a dog. You can meet the most unexpected people walking your dog in the park, or just around your neighborhood. And dogs have so much to teach us!
You could even have your psychologist write you a script for an emotional support animal (ESA) or service dog (which would require some training, of course), so that you could bring the pup with you virtually everywhere you go. NT has a service dog forum which has loads of info on it about this topic.
The other thought I had for you, if you like kids, is to sign up for a reading to children program in your community. There is such a need to promote literacy and just a plain old-fashioned love of books in our young ones.
I have trouble making friends, too. There seems to be something unapproachable about me that I've never been able to figure out. But I'm working on it! There is nothing "wrong" with being an introvert, Lemonbar (I looove lemon bars!!!); it's just the way we're wired. We draw our energy from solitude, whereas extroverts gather theirs from being around other people. It's a continuum; I'll wager you've got a bit of extrovert in you, too.
Don't give up on face-to-face support groups just yet.

You might find a better fit with a women's group, for example, or a depression group. I found one at a teaching hospital for chronic pain patients which is run by a pain psychologist that is a good group.
Maybe reach out to that girlfriend and tell her honestly what's up with you, bare your soul a little bit and ask her straight out for her support. She may surprise you. The two of you could maybe agree to have lunch once or twice a month, or do something fun together. Take your mind off things, just for an afternoon. Could really lift your spirits, and hers, too because it feels good to help someone you care about (no matter how many other girlfriend-girlfriends she may have!).
I know it's hard to ask for help, but it's important that we do so sometimes. Otherwise, we can get stuck. Human beings are social animals, after all, and we do need each other! Hope you'll stay close and let us know how you're doing.
Take good care,
Alison