vaginapagina | Period - A variety of problems

I posted about a week ago about the appearance of a period-like bleeding, nearly two weeks before I was due to start. I thought it was a repeat of two months ago, but it turned out to only last about four days. I then continued to take my BC Pill.
Since I got back from North Carolina for THanksgiving, I have been kind of having lower indigestion problems. Saturday and part of Sunday, I thought I was starting my period again, as I had some bleeding that required tampons. However, I wake up today, a day after I should start, and I haven't yet. I feel some cramping in my lower and upper legs, but I can't tell if it's from PMS or from my indigestion problems. Is it too early to assume I have skipped a period? Also, I don't think I am pregnant, as I had sex the day before I started my four days of heavy bleeding, and was still taking my pills. I am having sort of hot flashes.

I haven't skipped a period before, but some months before starting my pill, I would be about 5 days late. I know stress can stay a period sometime, so that may be it. Could something like Zyrtec(which I have been taking for a few days for allergy problems) be interfering?

Sorry my questions are spastic. Any help would be appreciated