I mean during a pandemic it's probably best to not get drunk with friends quite yet. Plus it's hard to remember birthdays of people you don't see regularly. I almost forgot my own father's birthday this last year because I have to constantly self isolate due to my work in healthcare with high risk special needs children. It sucks you weren't able to celebrate and that people forgot, but on the bright side you won't accidentally pass Covid19 on to anyone and vise versa.

You can make it up later when covid issues aren't a thing.

Well, if it was a possible planned night out, not exactly a great time to do it. But overall, it's just a drink or three, it's not that big of a deal. More sucks that you were alone. Next time, make concrete plans with the friend/s beforehand and communicate, that way there's less of a chance to forget.