hi there, you meant you took a pregnancy test or a blood test at the clinic to confirm the your HCG levels? Depending on your cycle length, a good home pregnancy test would be able to pick up the hcg from the day of your missed period if you're pregnant. if not, you can always take a few days later if your period still doesn't arrive. Good luck.
I heard doctor and nurse say before if 2 days later still negative means negative already..