Need advice!!

Last night my boyfriend and I had a few glasses of wine and we didn't use a condom for the first time in our relationship, I'm on the pill but I haven't started my next month of it yet, I was still on the sugar pills. My period just ended two days ago and it ended early so I haven't started my next month. We're going to get Plan B as a precaution because neither of us can handle a baby with our crazy schedules right now but for the ladies who have used it before, does it mess with your regular birth control?