What is this?

I don't know where to post this, but here goes..

I am on CD 20. As many of you know I have PCOS and started taking metformin 20 days ago..
I have been charting and no ovulation.

Now for my question:
since Friday I have been having something, I don't know what it is. I can't tell if it is spotting or my period. Its very, very light if its a period, but heavier than I expect spotting to be.
Its also a very dark color, not the bright red you usually see in a period...
Today it seems to be more like spotting but for three days it was heavier...
What is this?
Did I get my period?

Should I call my doctor?
I am so confused.

Re: What is this?

I think you should call the doctor - I know that mid-cycle bleeding is typical with PCOS and it could mean your estrogen levels are whacked out. Doesn't hurt to call. Good luck!