Do you think I'm pregnant?

I am on the pill, never missed one but I did take one 3 hours late in the first week of my pack, which shouldn't really have affected it but you never know, since I'm on low-dose. Anyway the last timeI had with my boyfriend was during ovulation, about 2 weeks ago. and... Not to be too graphic but his um, stuff didn't come out of me until morning, and I've read that thats a technique some couples who are trying to conceive use, so I figure it probably increases your chances. My period is due in 1 or 2 days, and I'm freaking out that I have pregnancy symptoms. I'm tired, I've had some mild tramping and even diarrhea. A friend commented that my looked bigger and I'm inclined to agree, but they're not sore or anything. I've been craving pickles but I've always loved pickles. I took a pregnancy teat yesterday (an early response one) and it came up negative, but there's only about 50% accurate that early. So what do you think? Coincidence? Impending period? Pregnant? Just looking for peace of mind.