Clomid 1st round

I recently had my first round of clomid at 50mg I have been trying to convince for a little over 2 yrs. I have a 3.5 yr old and when I got pregnant from her it was quick within the second month of trying. I don't know why I'm having such a hard time this time around. Round one at 50mg did not work for me I did not ovulate. I had Hystogram in February which the nurse told me it would "clean out" my tubes and make me more fertile for the next 3 months . I am have a cycle every month I'm just not ovulating. My doctor is prescribing a higher dosage of clomid for this next cycle at 100mgs. Someone told me I should ask for a progesterone supplement to help the clomid. Was wondering if any of you guys have taken the progesterone supplement to help the clomid.