Ovulation

So I am tracking of when i ovulate and yesterday was the darkest it got but still not as dark as the control line and glow said I ovulated 17. That day negative light line. I felt crampy yesterday. Usually I ovulate 11 or 12 or 14 and I might have late. Could I have trouble ovulating every month. Don't get it! Tracked every day since last period. Frustrated. Also taking fertility supplements to help could that be not helping? Been trying since November. Thanks so much!