Yes, it's possible to get pregnant while on birth control, and it's also possible to have a "period" if you're pregnant, but it may be of a different thickness, flow, or color. Because every woman's body is different, each woman will react differently to both birth control and pregnancy. You can take the pill faithfully each day and not miss a single one and you can still get pregnant...This happens to 1 in every 100 women who use birth control properly.
But how long have you been on the pill for? If you just started taking it, then you're going to feel a little weird for a bit. Because birth control is fake pregnancy hormones, you're going to pretty much feel pregnant, and that can include missing your periods or having them be lighter. It can be hard to tell sometimes if you're pregnant while on the pill because the symptoms can be so much alike.
If you're worried, wait and see if you get your next period and try a home pregnancy test - dont worry, it won't be affected by the birth control because the hormone it looks for is not present in birth control, but it present during pregnancy. If you just got your period and you take the pill like you should, then I doubt you are pregnant...But there's always that little chance.
Hope I helped you a little bit.
