When to stop progesterone?

Claire
Pardon my lack of abbreviations haha I don't know all the proper ones. I took my first round of clomid this month, then had a prog level of 8.2 after I ovulated so my doc put me on progesterone. AF is due Saturday and I've taken 4!!! early predictor tests all being negative. If I keep taking the progesterone it will keep me from having my period (and moving onto the next month). Soooo the dr said to test Saturday and then if it's neg to stop taking prog but I'm certain I'm not preg bc I've had 1 healthy boy- 3mc and 2 ectopics all of which I always know a week before AF was due that I was pregnant. So can I just stop taking the meds and get on with it?