I had light bleeding about a week before my period was due, have been unusually tired, and cramping without bleeding now..could this be from birth control pills or could i be pregnant?

Yes and Yes: If you have been taking your oral contraceptive daily, odds are you are not pregnant and this might be an adverse effect to the hormones. It could also be the result of your contraceptive interacting with another medication you are taking. If you haven't been taking your ocp's reliably, you might have had an attempted uterine implanting that didn't hold, cause your uterus to cramp and expel it.

See your PCP.: The answer is both. If you missed a period and you are usually regular, see your pcp to get a pregnancy test.

From the pills: You had light bleeding on bcp, then had a regular period at the usual time. Most likely the light bleeding you had was break through bleeding and you are likely not pregnant, since you did have a normal period at the correct time. However the chance of break through bleeding increases if you miss or were late on your pills. So i recommend a pregnancy test to be sure and take bcp same time.