Women do not menstrate while pregnant, so no it is not possible. It is however possible to just bleed while pregnant.
Many women make the mistake of calling any bleeding a period, when you can actually bleed for many dozens of reasons. As another said, the only way to know if you're pregnant is to take a test.
That happened to me! The month before I missed mine my period was only 2 days and I was off birth control.
It's possible, yes. Some ladies have "periods" throughout their whole pregnancy. Only way to truly know is to take a test (: good luck