A few days ago, I told a girl that I fancy her, and she said she fancies me. We said we'd talk about it in person whenever we were both free, which was the next day.
However, that night at a party, me and a closeish friend ended up getting very drunk and, er, doing some stuff together which probably wasn't too great for our friendship, and now I don't want to go out with the girl from the first paragraph (I also don't want to go out with this girl).
My problem is how to explain I don't want to go out with her because of what happened that night, without actually telling her the reason. She'll obviously want to know what changed, and me and the girl from the 2nd paragraph decided we didn't want people to know what happened that night, which is why I can't tell.
If I don't give a reason, she'll probably get pretty annoyed and think there's something wrong with her, or I was messing her about.
Any ideas about how to tell her I don't fancy her anymore, keep my secret, and stay friends with her?
Her = girl in the first paragraph, not the friend at the party.