I thought I knew about cycles and charting and whatnot but after having ds my cycle days vary greatly....30-41 days. More recently they are getting shorter and closer to my normal 28 day cycle. My average now is about 35 days. I read in another post that cycle lengths can change but not the luetal phase unless I'm using herbs or creams which I'm not. I've been ttc for 5 months now and I've tried opks that come up positive after I ovulate not before and wasthinkin if I could figure this out it could help me identify my fertile week better.