First of all, hoping you’re feeling better by now. Judging by the honesty you’ve shown writing this post, i think you’re a decent person, and fully deserve better.
I think it’s totally natural that you’d feel miserable after being stood up etc, horrible behaviour of others. But please try not to ‘self-doubt’, and hope you knkw it isn’t your fault. I did a solo one this year, and I understand and sympathize with what you wrote down.
In general, if it’a not a decision that’s urgent, I would hold off on deciding wether it’s ‘my last’ or not. I was certainly tempted to say ‘it’s my last’ after this one (and during many moments), but I am going to see how i feel, and i hope you do too. It will help uou make a more “informed” decision, and not feel bad about yourself.
For what it’s worth, I wouldn’t have stood you up! Again, hope u feel better