Plan B and sex stopping period?

[kangaroojy]

Hello. First and foremost, I am 99.9% confident I'm not pregnant, so I am pretty much asking out of other worries and curiosity. I've got two questions, but first a quick summary:

My cycle varies between 28-30 days with 5-7 day periods, I have never missed one, and they always come on time. My boyfriend and I had sex (with a condom) on day 4 of my period, April 21st. I filled the condom with water after we were finished to make sure it wasn't torn, and it wasn't. I allowed him to enter me (before he climaxed, so there was no cum, perhaps the potential of pre-cum only) without a condom on for a few seconds. My period ended up stopping immediately after sex, which really threw me off because there was no way with the amount of bleeding and stuff before sex that I was done. I knew it wasn't a sign of pregnancy because a) I wasn't ovulating and b) pregnancy can't happen that fast, but worried that my boyfriend entering me without protection was a bad call anyway, I took Plan B One-Step about 7-10 hours after we had sex. My period was pretty nonexistent for the next couple of days, maybe a pink drop here and there, and then suddenly I began to bleed heavily for 2 days and stopped on April 25th. I've read that Plan B can cause you to bleed after you've taken it, so I attributed it to that. On/before my next ovulation date (I chart my periods and cervical fluid to get a general idea of this, and have been fairly consistent) I got no stretchy cervical fluid at all, which I always get around that time. Up until a couple days ago, my CM was very watery/sort of creamy. My boyfriend and I had sex with a condom (again, no tears) on May 7th.

I was expecting my next period May 18th. To be sure and ease my mind, I took a pregnancy test this morning and it came back negative. So although I am confident that I'm not pregnant, I am still wondering- what could the effects of Plan B be on my period? I know the pill can screw with your cycle, but I'm wondering how it works specifically since I took it /on/ my period. I know that was a weird and paranoid call and I won't do it again, but I still don't know what to expect.

Secondly, does sex stop your period, or pause it? If so, why?

Oh, and I guess a third question: if I am pregnant, I would know by now, correct? With the test and all.

[Karyn]

If you were pregnant, you would have gotten a positive test result by now, yes. Unfortunately, there's no way to predict what the Plan B will do to your cycle. The effect it has doesn't depend so much on when you took it, but the reaction each individual person has to the hormones. Many people do find that it causes some irregularities (their next period arrives early or later than expected) but there is no way to know for sure how your body will react.

Per your period stopping, sex doesn't cause periods to stop or pause. Sometimes they do that on their own, though - it's just one of those things that bodies can do. It sounds like perhaps what happened is your period was a bit shorter this time around, and then you had some extra bleeding due to the Plan B, but there's no way to know that for sure.