In order to allieviate the stress
associated with situations like this, you can begin by taping a copy of your ID card to the bathroom mirror, along with a few pictures of yourself, so you won't have to worry if you've recently had a haircut
or not. You wake up, and eventually, you're going to head in for that morning pee, whether or not you remember who you are. If you're lucky enough to have arrived safely at home, you'll be able to at least know your name and where you live, if nothing else (keep a notebook with pertinent information if you're going to need it, leave a few post-it notes
The method works, I know, I've tried it. I've caught myself in front of my mirror after a serious night out on the town, staring down at that picture, going, "I must be... David." and I know I'm not the only one. After an incredible night of drinking yourself stupid, you wake up, and you don't remember that last night. Hell, you don't remember who the fuck you are! This is a disastrous feeling to wake up with, but heck, you're an alcoholic with temporary memory loss! So get used to it, or quit the shit altogether.