Uh oh

So, a few weeks ago, I got really drunk and had a one night stand, it was on the 4th day of my fertile window and I kind of blacked out during it so I only remember parts, but I dont remember if he came in me. Im on the pill, but of course, I was on antibiotics for bronchitis, I took a plan b the next morning. My period is supposed to start tomorrow, could I be pregnant?😫