20 days late

So according to the app I am on day 53 of my cycle and 20 days late. I have been taking metformin since the beginning of the year (February I believe). I spoke to my OBGYN after I was 2 weeks late and she put my on 7 days of progesterone to jumpstart. I am currently on day 6 of the progesterone and still nothing. All pregnancy tests and ovulation tests have been negative. Just curious if anyone has ever experienced anything like this? TIA!