Metformin USERS!!!

Jennifer • I was diagnosed with PCOS 10/26/15. Expecting our 1st in Jan. 2021!!!!
Hey, so I have a question before I go calling my GYN. 
I just started metformin. This is my first period on it. I have been titrating from 500mg-1000mg-1500mg and next week is 2000mgs.
I "normally" I say that loosely bc I have PCOS. And, it's only been 1yr consistently that I've had AF
But, normally 3-4 days long and generally light AF. 
This month however, I've had medium-heavy flow and I've been bleeding for 7+ days!!! 
Has anyone else experienced this? Is it normal and my body's just not used to the meds yet!?!