test can become positive after 3-7 days of a missed period. If they are not positive in the first instance, you may repeat them after a couple of days as they are not so sensitive and sometimes fail to detect urine hCG
levels if low. Blood tests detect pregnancy as soon as 6-8 days after ovulation. Since you have followed the stipulated schedule, there are chances that you could conceive in this cycle, but it would have been better if you had planned it two days earlier as you ovulated the day before. Please consult your doctor for further advice. Take care.