What Causes Heavy Menstrual Bleeding After Stopping Birth Control Pills?

My fiancee stopped taking her birth control pills two weeks ago because we want to start a family. Immediately after ceasing the pills she got her period, but she isn't 100% sure that it was actually her period because she was bleeding way more than usual. She said it hasn't been like that since we were in high school, the last time she wasn't on the pill (nearly 9 years ago!). We are wondering if that was actually her period or it could have been something else, and when the best time to conceive would be.