You can get through it, Jo. You'll feel awesome when you do! I went to a party Friday night (at a bar) and it was a bit weird at first, but after awhile your sights are set on leaving soon as it's almost over anyway and by then there's no point. That's how my first party went anyway. I was really proud of myself for getting through it...far outweighed the pleasure I would have gotten from the fleeting drunk feeling, not to mention the guilt and disappointment that would have followed.
You can always use the "I'm not feeling 100%" excuse to not drink, too. That was gonna be my response if anyone asked, but no one did!