Birth Control Pills?

I've been on birth control (low dose: Yasmin 28) for 6 months. I went on the pill because I had really heavy, painful periods. Well, 6 months later, and my periods are slightly less painful, but still heavy, which is a major inconvenience. I hate getting my period! Is there anything else I can do about this? Also, could having a very heavy period, even on birth control, be a sign of an underlying problem?
Answer:
the same thing happened to me and someone told me to exercise and your body will need more blood thus lessening your period flow. which worked for me plus more exercise is always good :)

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