period while pregnant?

I just wanted to know if anyone got a period while pregnant. I got a bfp on 8/31/16 and started bleeding on 9/7/16 with cramping which is like a real period. I haven't tested again. My pcp did a blood test on 8/31  which confirmed early pregnancy. I am just waiting for the results for a sonogram. I just want to know if anyone experience some like this or similar before.