17.8 is a great number to show you ovulated! That's good news! You're halfway there! However, I'm sorry to disappoint you but there is really no correlation between progesterone levels in the luteal phase of your cycle (the time between ovulation and pregnancy) and getting pregnant. You do want your progesterone to STAY high, because if it drops it will trigger your period, but as far as the testing mid luteal phase it really doesn't indicate one way or another.
Good luck though! Definitely let us know the results next week!
A progesterone test simply indicates if you have ovulated or not. Your level does indicate that you did ovualte. It in no way indicates if you are pregnant. I have seen very high levels before and yet patient was not pregnant.
Wait it out until your period is due and take a test. Good Luck!