Could I still be pregnant even though my blood hCG test was negative?
I had a blood hCG pregnancy test 3 days before my period was supposed to start but it was negative. If I were pregnant shouldn't the test be positive?
You are correct. A blood pregnancy test is usually positive 3-4 days after implantation, and because implantation usually happens 7-9 days after ovulation, then the blood pregnancy test is usually positive 3-4 days before the period is supposed to begin. However, this all depends on exactly when you ovulated and when the fertilized egg implanted.
If ovulation happened even a couple of days later and if implantation happened later (it can happen up to 12 days after ovulation) then the blood pregnancy test will not be positive later than you expected.
You may want to retest again when you are missing your period.