Your progesterone does increase when you are pregnant, but if this is not what they are looking for, I would think it is unlikely that they would confirm a pregnancy this way. I had the test the month I got pregnant, and reckon I ovulated a day or so before the 21 day progesterone test, so would have been pregnant but maybe not implanted. When I went to the docs for the results, she was all ready to refer me as the results were so low - 5 I think - but I had my bfp by then!
I think charting your temp is the only way to monitor ovulation - I knew I had ovulated late that month from my temps, which is why the results were low.
fingers crossed for Sat - are you going to test?