It's very possible that you could be in the early perimenopausal stage. It's also not unheard-of to be pregnant (just ask Steph

), even on the Pill. (My last child was a Pill baby.......actually, he still IS a pill, but he's 13, and that's a subject for another day

.)
For what it's worth, I've been in perimenopause since I was 40, with hot flashes and irregular periods beginning in earnest around age 42. Now I'll go for 3-4 months without a period, then when I do start I'll flow for several weeks......usually fairly lightly, but sometimes I'll need a large pad and super-plus tampons to control it. (I had an endometrial ablation for severe and prolonged bleeding a couple of years ago, and it helped reduce the volume somewhat.) It's different for every woman, and of course, if you're seriously concerned, you'll want to check w/ your OB-GYN.