AF is almost over!

A.
So ladies I was given provera to help me get a period for blood work and stuff, well AF will be over in a few days and I have PCOS and don't know when my next cycle will be🙄 I'm trying out an OPK this month but don't know when to start since I do not know when my next cycle will be, my last cycle was back in January 🤷🏼‍♀️ any suggestion as to when to start tracking? Thanks in advance!