Awkward situation with coworker (27M) (38F)

I recently had a situation come up with a coworker and it is still upsetting me almost every day at work.

I thought that he was flirting with me and it seemed that as soon as he realized this as soon as I flirted back a bit, and he immediately put space between us, avoiding me at work for weeks.

When I see him now, I feel uncomfortable, embarrassed and a little bit resentful, even though it’s not his fault. I try to remain as cordial and professional as I would with anyone else.

I am a little bit older than he is, and I have to be honest, a part of me feels a) like even more of a jackass for possibly misinterpreting b) insecure that he isn’t interested because I am somehow not attractive enough ( I was very pretty when a bit younger and I think I still am and people tell me that I still am, but I still harbor this fear). Also, for context, he is not extremely physically attractive or anything, just a regular dude.

Anyway, I hate seeing him at work because I just feel exposed and humiliated. I am not sure how to be “normal” around him without these feelings getting in the way. I am also terrfied that other coworkers somehow know about this situation and I just generally want to quit and never come back 😞

I-(38F)Him- (27M)

tl;dr A coworker seemed to reject me and now going to work sucks