No, even if you had just ovulated and your egg has been fertilised, it is too early to test. It takes about a week for a fertilised egg to travel through the fallopian tube and implant into the lining of the uterus (womb). The hCG produced by the egg can only be detected in your urine once the egg has implanted. If you test before the egg has implanted (typically about 7 days before your missed period), there will be no hCG present, so a pregnancy test will always give a negative (Not Pregnant) result. The earliest you can test with the most sensitive tests currently available is 6 days before your missed period (typically 10 days after ovulation).