Withdrawal bleed after stopping birth control

sara

I took birth control for 3 weeks before starting the frozen transfer prep. I’ve taken birth control two other times before fertility treatments and it’s always been a normal flow period. This time it’s very light. I’m cycle day 3 but It seems more like day 5. Has this happened to anyone? Maybe my lining just didn’t get thick on the birth control. My last period was 8/20 and I started the birth control pills 8/21. Topped birth control 9/11