Anyone have any thoughts? Ovulation?

I went off the pill in November. I didnt get a period so the OBGYN prescribed Prometrium. I got my period on March 3. On March 16 and 18 I had ultrasounds and the DR saw no mature follicles. If I tested negative for pregnancy I was supposed to start Prometrium and Clomid, but my DR called me back and decided to wait another week, why? Also, eventhough he isnt sure I am ovulating I have been doing OPK's and tested positive today?