negative OPKs after Chem preg

Jo • Due April 23rd with 1st. Married 2015. DH & I together since 2010. Mama to two angels. 👼🏻👼🏻
So we had a Chem preg on 8/26 but doctor said once o stop bleeding (which was 4 days so normal period) we could start trying so I'm trying to pin point ovulation and all my stocks have been beyond negative. Wtf is going on.....