Don't be embarrassed.

It's part of the risk of dating/hooking up.
And if it makes you feel better...I've totally been that guy. I've gone out on a date, had a legitimately good time, hooked-up...but then ran into the guy unexpectedly while I was out with friends and was
totally fucking awkward about it. Even though I legitimately liked the guy. The guy was out with people, I was out with people...we made eye-contact but I didn't go over and speak to him. For some reason I just felt like it wouldn't be appropriate if I did.
He shot me a text the next day and was like "Yo, you didn't have to be a stranger..." and I told him that I didn't want to bother him or his friends and be weird or anything. He told me I was being silly, and we out again.
I guess what I'm trying to get at is that he probably wasn't
meaning to be an asshole. I think that, especially in the gay community with hook-up culture and all, sometimes it's kind of hard to read if what you're doing with a guy is an actual date that could lead somewhere, or just a prelude to a hook-up. Sometimes people get caught-up in the awkward gray area.
Don't beat yourself up either way.