PCOS and Prometrium question

Long time lurker, first time poster.

I was diagnosed with PCOS a couple of years ago however in the last year my cycles have gone haywire going from every other month to completely MIA. The OBGyn presciped progesterone to induce a period. I did not do so well with the medication (headaches and way too emotional) so she switched the prescription to prometrium instead. I took a 7-day dose in january and a couple of days later had a "normal" cycle which lasted 5 days. As I am prepping for IVF in May and had to retake prometrium (March 9-15) to induce a period. I had minimal spotting on saturday march 19th, light flow on sun and monday and nothing today. I should mention that i started BCP last night per the obgyn. 

Has this happened to anyone else with prometrium ( really light cycles) ? Do you think maybe the BCP also put a stop to it ? If so it was fast acting 😑

Thank you for your help !