I think you have few options
1. Don't go. Since you are very newly sober and your drinking revolves around social events, you may need to simply avoid them for a while and until you get some good sobriety/tools under your belt. People miss weddings all the time for all sorts of reasons, your health and sobriety sounds like a fine reason to stay home to me,
2. Just go to the wedding itself and skip the party afterwards. The marriage ceremony is the most important part of the day anyway, so it's perfectly acceptable to go and honor the couple there, maybe bring a gift, and then head home.
3. If you do go, have a plan so you can leave at any time if the temptation is too high. This sounds pretty risky to me so early on in sobriety, and it already sounds like your friend might be drinking anyway, so you can't count on that. You'll need to have an iron clad plan to simply leave on your own if you need to.