Self-Sabotage

I hope it's not weird to post this. About two weeks ago, I took a single-day course and noticed a cute person there signalling interest. It was the first time I've felt mutual attraction and safe in the interaction, but we didn't talk. I think they were testing the waters, and even though I kept thinking of how I could positively respond, I ultimately didn't act. My mind kept rationalising based on former negative experiences about "being too much" or "not enough" why I had to be careful. This person was trying to set up a way to approach me, but I ended up leaving early to catch a bus urgently (a bad habit of anxiety I have) and lost my chance in the process. It's rare I feel that way about someone and it's worse when this person is the most attractive all-round impression I've come across. As I left, they looked really disappointed which makes it hurt more. I've been severely depressed since because I don't feel confident I'll have another attraction like that again. I've waited so many years to feel seen like that, to feel like someone wanted to know me, and I feel like I betrayed myself. I have a lot of self-hatred and deep regret. I don't know what to think anymore and I'd appreciate some perspective or advice on how to cope with the loss of an opportunity like that.