Meds but still not ovulating???

My doctor put me on my first round of Femara to help with ovulation. I was tracking with clear blue and it gave a smiley face on days 19 and 20. I went in for an internal ultrasound and blood work. Nurse said today that my progesterone levels were low and I probably didn't ovulate. Anyone else experience this and is there anything I can do differently to help those levels?