The first girl to ever show interest in me blocked me for no reason. How to not feel defeated, scared, alone?

I'm 24, been on dates, never been in a relationship. I'll admit I feel like I'm falling behind my close friends, all of whom are in relationships. It's scary to think it'll never happen for me and it's sucky to feel like you're no one's number one. I get they're closer with their partners, it makes sense to me, but it's still not nice. One of them actually got engaged recently and while I'm elated for them, it just amplified the fear and the sense of lacking.

I thought that would finally change with this girl I met. I've gone on dates, but I've never forced anything just to be in a relationship with someone as I'd like a genuine connection and feel like I'm capable of it. It went really well, she seemed really interested, talking and flirting just came natural. Woke up today to being blocked on everything. There was literally no reason to it, she's visiting a friend, I asked her how long she's staying there yesterday, she responded until Friday. I saw her text this morning, went to reply and it didn't go through. I then went and saw I was blocked on everything and had no way to contact her.

It's a very defeating feeling, because I don't think I did anything wrong. If she didn't want anything, changed her mind or whatever, she could've just told me so. And now I feel like an even bigger idiot because my friend hosted a bit of a get together last night with the engagement being the occasion, everyone and their couple was there, talking about how forward they're all moving and I was telling all of them how well it's going with this girl.

I feel so embarrassed and down right now and I feel even more alone now than I have before and I don't know how to help myself.