My daughter has Asperger's (so does my mother), and it is one of my main triggers as well. The thing is, once you let one trigger go, then they all go. First you drink because of your child, then you drink because you're bored, then you drink because it's wednesday...
So you slipped up. It's okay! Get to the hotel gym, that's a great start.
When I'm frustrated, angry, sad, whatever and I really feel like drinking, I've noticed it helps for me to listen to music turned up WAY loud on headphones--sometimes I even dance like a fool and get all that yucky energy out!