Ovulation prediction wrong?

Tanya

I was cramping on the left side on feb 7th and 8th, on the 8th I felt a gush in my panties and had so much thick, clear/ white stretchy cervical mucus a lot of it. So I new I was ovulating I was also horny and the day after. The ovulation predictor says that I am supposed to ovulate on feb 11. But on feb 10th and 11th I had no cervical mucus and feeling period cramps and gas in my uterus but I took clear blue ovulation test on the 10th and 11th and it have 2 dark lines and predicting that I’m ovulating I am a little confused and need some answers Lol.