I've been tracking with bbt and opks for 5 cycles (while ttc#4) and this cycle was the first where I didn't get a 1 degree increase the day after a peak opk. I had a 0.5 degree increase that then gave temps that were just over the coverline. Today I'm 11dpo and got a 1 degree increase in bbt. I tracked with opk and bbt for 4 pregnancies (one miscarriage), so I'm confident that I'm doing it correctly. Does this mean I ovulated yesterday and my earlier peak opk was incorrect? Or, is it a possible sign of pregnancy? I'm 37, so I know my cycles might start getting odd. Please help! Any thoughts?