On chlomid 50mg i had a progesterone level test done at cycle day 21 and nurse said my level was a 7.5 can i still get pregnant at that level?

Yes you can: Yes, you definitely ovulated so it's still possible to get pregnant. When you check a progesterone level it measures just a single point in time. If they measured it again in 12-24 hours the result could be different. It's true though that we want progesterone to be > or = 12 for a strong ovulation. If you don't conceive they might go up on Clomid (clomiphene) dose.