A trick that works for me is to accept the nervous, sick feeling, and find a place inside myself to put it. Imagine a room labeled, "anxiety." Just put the feeling in the room, don't try to make it go away. Then mentally go to a different room for awhile.
When I learned to stop fighting my feelings but to not dwell inside of them all the time either, they got to be less of a handicap.
I second LaTeeDa about anxiety resulting from helplessness in the face of something one would like to control, but can't. So, act from a position you can control instead. Once you accept that he's going to drink, you can consider your choices. If you want to act as if everything is normal, that's one choice, if you want to not see him when he's drunk, that's another. Whatever works for you, you're free to do. That way, you're acting, not reacting.