Odd cycle changes?

Hey! My cycles have been a bit odd the last few months, I've always come on my period 14 days after ovulation (I track ovulation and have done on and off for the past 3 yrs roughly). The last 3 months I have been coming on my period around 11DPO, does anyone have any experience with this? Can it mean something isn't quite right? ever since it's been happening I've also started getting shockingly painful ovulation pains to the point I can't move for most of the day. I've always had cramps when I ovulate but the last 3 months has been crazy. If I am coming on earlier that I used to, will this stop me getting pregnant? Many thanks x