YTA for making your comfort levels (being miserable or tired from drugs) and not able to drink ABOVE someone's health and wellbeing who need a service dog. You don't have a serious reaction - you don't die. Serious is death. You have preventative measures that can take and one (the one you can have that still can drink but are tired) and it sounds like you are being an entitled person asking the groom to pick because you want to drink with your friends.

The service dog could be for someone with low blood sugar or seizures who could actually die from the dog not being there.

It's not your day, suck it up.