Don't finish the can you bought. I hope you didn't keep a can around? Make damn sure you clean out everything. Cars, lockers, bags, house, etc, then get on May and post a new Day one when you don't have a dip in.
The first 3 days suck no doubt, but dude you have to want it bad because there will be plenty of other days that are gonna be hellish as well. You do not buy a can. You do not keep a can around. Not even dust...I would snort that shit on a bad day. Clean it up and get back with your group.