Seconding the therapy suggestion. Making the connection between meeting new people and being a worthless human being is a huge sign that there's something seriously wrong. It's been said before, but you're not ready for dating. You need to build yourself up first, lest you get trapped in a relationship with a huge power imbalance due to your low self worth. You're better off seeing a therapist and making your sense of self stronger first.
I used to think therapy was bullshit and admitting a sign of weakness, where some loser Liberal Arts person would tell me why and how I, a successful professional, was a failure. That was mixed with intermittent feelings of . . .
Went to a Meetup.com pub crawl and I think I may have met a bunch of people (we found a common interest in nightlife, books, etc.). Strongly doubt any of them will ever call me back though, I feel like a worthless human. Do I even want to find out if they will? This terrible anxiety over things like this over the years has destroyed my life.
. . . yeah, this. Not as crippling as yours, mind you, but I'll share this with the crowd: feelings of "Yeah, my ex-wife can do better than me. Why isn't she dating a doctor?" tanked my marriage. It's important to have an objective conception of our self-worth; but it's also important to
have self-worth in the first place. What's odd is that our brain compartmentalizes! For instance, I was perfectly confident in professional settings. Even with friends. The doubt crept into romantic situations and bludgeoned me over the head. It's undeniable that we, as social animals, derive value and pleasure from finding our place within bands of other humans.
I haven't undergone formal therapy yet, but my previous girlfriend was a clinical psychology Ph.D. student, and through our talks, I realized that it's neither confrontational nor exploitative. It's just someone trained in human nature guiding us along the path of making our own decisions. Sometimes our map (i.e. brain) doesn't work correctly, and those are more severe cases; however, I can offer you this much: I was walking to a job interview a few weeks ago and started to feel nervous. Asking myself internally, "Why are you anxious?" actually helped. This may sound laughably simple, but it goes to the core of what others are saying: the worst case scenario is that you didn't click with some people, which puts you
exactly in the situation you are right now.
Also, 7 months isn't a long time. In nearly two years of being in the city, I can honestly say that I have a handful of really good friends, one of whom is moving away (and always busy with his boyfriend) soon. Building and strengthening social circles is a lifelong thing. Finding friends, at least for me, is much harder than finding a date. Keep at it. Things will eventually settle into place there, but I won't lie and tell you it's easy, unless you slot nicely into a preexisting friend group, which rarely happens.
Best of luck to you. You'll get there.