I'm [22/M] and did something I feel really guilty about.

I just want to be 100% honest I guess and the easiest way for advice is the internet..

Recently went on holiday, got drunk and spoke to some friends about what to do next, was about 2am. Looked for places that were open still, think it was a Sunday so most were shut. Found out there was a gentlemen's club open and they gave "erotic massages" of which I genuinely didn't know the meaning of. I thought "might as well go there and might even get a massage! Could be fun" so I left by myself as my friends couldn't be bothered to do out, although it didn't turn out to be a massage at all but 30 mins of oral sex... nothing less nothing more and a condom was worn throughout.

Anyway a few days after that I met someone. I've been honest with them about everything in my life and they've been honest with me, but I just can't seem to tell her this. If she asked I would tell her as I hate lying but I think she hasn't asked due to the fact she doesn't think I'm the type to go, I'm not sure. I feel so guilty for some reason about it and it keeps me up at night. I want to tell her, but I don't want her to think I do that sort of thing all the time.

Also if I tell her, is it just to relieve my guilt but it will make her feel shit? Is that worth it? It happened before we met so is it relative to us as people? I don't want to hurt her.

I would NEVER go back to a place like that and as I say it happened before I had even met her. If I told her do you think she would stop speaking to me or just.. judge me? I really don't know what to fucking do. Has anyone had any experience with this sort of thing before?

Sorry for the rant guys, maybe I'm over reacting but I really feel shit.