What Could Cause Heavy Periods?

Hello, I am 51 years of age in good health, however menopausal. I had my mirena removed 6months ago. No periods for 11 years has been heavenly !! I had hot flushes and my gp put me on menopause pills, now some 5 weeks later, I have a period, now day 4 and i feel heavy. I am seeing my gp in 2 weeks, could these pills have reaked 'havoc' ?