ovulation after miscarriage

I started bleeding September 21st for my miscarriage and had what I assume is my first cycle October 21st. My progesterone blood work should it went back down like it was supposed to. I am on cycle day 12 but I haven't seen any dye on the test line of an ovulation test. I'm wondering if they are supposed to start showing dye and then get darker as I get closer to ovulation or will they be blank until I ovulate and then just show up? Normally I use the digitals but this month I bough cheap ones on amazon so I'm not sure how they are supposed to work.