Extended periods on metformin

[Ibelieveitwil]

I have been on metformin XR 1500mg for just over a month and have had my first period 30 days after my last. The thing is it was very light (wouldnt even fill up a pad) I am now on CD7 and since CD5 its started getting heavier. It should have started finishing off by CD7. Its not my usual heavy period but its a period nevertheless much lighter. Should I be worried, is this just due to my hormones regulating from the metformin. Any advice would be appreciated as I am desperately trying to conceive and it doesnt help that my sister just got a yesterday and showed me all 7 or her tests I just want to start BDing but just wont stop. Please ANY advice