jules - I felt the same way... even though I knew I had low progesterone, and my doc wouldn't let me take prescription stuff until after a BFP, I still couldn't bring myself to use the OTC stuff

when I switched over to a specialist, he told me that usually when the progesterone is low, the best method is to try to get it higher on the front end (by giving you healthier/larger follicles) rather than try to save it on the back-end. So he upped my dose of clomid, which got my progesterone levels to a nice normal level for the first time (previous 4 cycles had blood tests with low progesterone). And I DID get my BFP then! he put me on the prescription stuff anyway just to be safe, but it was nice to know that I wasn't hovering on the edge of shedding my lining!
Oh... and no spotting on the cycle with my BFP... had 2 suspected chemicals before, but was spotting by the time I got a line on a test.