Nope, you're right, I forgot it's your brother's bachelor party. Can't miss it.
It's not easy, that's for sure. I'm much older than you, so don't have a lot of the same social pressures. I wish I had some good advice for you. Maybe after a year of sobriety it will be second nature, but that's not helpful now - so I think it's all down to the cliché - one day at a time.