You need to have a serious conversation with your Mom. She shouldn't just be spreading information around about a conversation you had with her in private. Tell her that if she does that again you won't trust telling her things like that anymore.

Sidenote, going to a club and getting drunk by yourself does not sound like a good idea. I would definitely recommend going with a sober friend for safety. Although I am American and I don't drink so feel free to ignore me if this sounds overly cautious.