A month on metformin and no period

Emely
Hi ladies, I've been ttc for 2 years without success, my doctor prescribed metformin a month ago, my last period started on July 5th, it lasted 5 days and I haven't got it since then. I'm on CD 62 , negative hgc and lh , tomorrow at noon I'm scheduled for an ultrasound, probably I have ovarian cysts again