Random Periods

I was diagnosed with PCOS at the end of December. I take 2 extended release Metformin twice a day (so 4 pills) and then 1 Spironolactone twice a day (2 pills). I went from not having a period and needed Provera to start, go having a period every 2 weeks or so. My current cycles started just 8 days after my last one ended. I have an appointment with the doctor next week, but have anyone here experienced this? Could it be the medication? What was your experience? What was done to regulate? I'm just unsure what to expect.