hi LtL,
You are here now, that is a start. I'm guessing, but someone else can confirm that starting again after one night won't involve the full withdrawal sequence, although I bet you're feeling pretty crap still right now because your body really doesn't like those toxins in it anymore.
We are all pretty much the same here, we're not able to just do one drink, and we just have to realise that. I don't think the number of days without a drink changes that.
Day 1 is always pretty awful, but you will get over this - try and hang onto how much better you felt when you weren't drinking and know you can feel that way again very quickly.