Changes in Menstrual Cycle in Ladies Only Posted December 30, 2013 Ummm. I did my first Whole 30 in September 2012 and didn't get my period again for 3 MONTHS. (I went back to eating bad food almost immediately after the 30 days were up. I'm 30 yrs old today.) It wasn't any inconvenience then as I wasn't sexually active so I had no worries. But now I want to do another whole 30 in January (and hopefully the good habits will stick!) and I'm sexually active, and while I'll of course take precautions, I don't want to constantly be worried I could be pregnant. Is there anything I can do to keep my monthly pal around?