Can p90x cause anovulatory cycles?

I started the FAM method of birth control and so far it seems my temperatures are all over the place. Some are below 97 and some above 98 in weird places. I am doing P90x, and I know that strenuous exercise can cause anovulation, but is p90x really THAT strenuous? It's 1hr to 1hr 15 min a day, 6 days a week and i dont feel overworked at all! I also run a mile 3-5 days a week. Yet I still haven't lost a lb. I'm not overweight, but my body fat is around 28%. I came off the pill about 7 months ago, and I'm only 22. Could the pill STILL be wrecking having on my cycles? I still get a period but its fairly light and only about 3 days, no pms either. I do want to have a baby someday years from now, so I would like to know if I do have a problem, that way I can treat it early.