what's this?

Hi. I am 26 years old. I have always had regular cycles to the date. TTC for about 6 months. Went to the ob/gyn, she said get a CD21 progesterone test done, Level came 11.1 ng/mL. She said it was too low and showed that I wasn't ovulating properly. She gave me pregnacare - conception tablets (daily) and prolifen (2nd say of periods for 5 days). I took just the pregnacare for a month and the test results were 11.4 ng/mL. The next month added the prolifen from 2nd day of cycle for 5 days. CD 21 test came at 9.6 ng/mL. I was expecting an increase... then why the drop?
Also I am overweight. I weigh 74 kg at 5 ft. 8. Can losing some weight help to kick start proper ovulation again?
Thanks.

[arwamay]

Oh and prolifen has the same formula as clomid, while pregnacare is a daily supplement.