My period is 18 days late. A negative pregnancy test by the health center when I was in for a sinus infection when I was two days late (they did it in case they had to give me antibiotics, I wasn't worried yet.) I took another test that came out negative on Thursday. I'm fairly confident that I am not pregnant.

So then why haven't I gotten my damn period?? I have no unusual discharge (there is some, but it's not alarming), some cramping but I'm also battling emerging lactose-intolerance (my life is a wreck) so that's kind of difficult to trace to my uterus or whether I forgot to take my lactaid pills before dinner.

I've been on three courses of antibiotics since May, if that means anything. I'm not on birth control. And, uh, I've never been to the gyno. I'm only 20 and just sexually activated last year, only had 2 partners both of whom I KNOW were clean.

I'm legitimately terrified. I'm going to make an appointment as soon as I get back to school (because free) but that's not until next week. Help, please.

ETA: My periods have been increasingly irregular in the past six months, Kirov helpfully pointed out that this is an important detail!