Why do I have anxiety after alcohol?

Seretonin. While alcohol may temporarily cause you to feel relaxed (it works on gaba receptors in the brain and acts as a depressant), long term use may actually deplete stores of the "feel good" hormone seretonin. If you are having a reaction to alcohol, i suggest abstaining and trying a non-alcoholic alternative.
Rebound. Alcohol is an inefficient anxiolytic--when it is withdrawn u experience a surge of anxiety pts with pd often have an attack the morning after a binge drinking bout.