progesterone supp post ovulation-who takes?

Mary • I will not give up before my miracle! Mother to 3 girls-21, 15, 7 4 angel babies
So I'm supposed to start on Wednesday per glow. When do you stop the progesterone? A Negative test on Wednesday or give it a couple more days. I'm scared to stop too soon as I've seen posts on here with it taking two days or so post start date to get a positive.  
This cycle is not my norm as I've been taking extra supplements and seemed to help lengthen my cycle. Norm before was 24-26. I had a miscarriage 2 cycles ago.  Taking B6, coq10, evening primrose only  1st 1/2 cycle, prenatal vitamin, fertility plus supplements.