I had sex possibly within my fertile window, but I'm unsure because I didn't start keeping track of my cycle until last month. We used a condom, but I'm not sure if it broke or not. Since the guy didn't say anything, I don't think it did. I didn't take plan b after, but I took it on April 19. My period is supposed to come from yesterday until Tuesday. Could last month's plan b make me late? I've been having breast tenderness, but my nipples don't hurt. Does this seem more like PMS or pregnancy, I know it's hard to differentiate.