Doc say to wait atleast 60 days if you AF dosen't come, then to see them so they are able to put you on a medication to jump start your AF. Usually I would say that is a HPT and a blood test came out negitive then more then likely you are just really late. Are you irregular with your AF? If you are having regular unprotected sex then there is always a chance you maybe prego. I would say to make an appt to see your doc so they can help you jump start your AF (prolly put you on Provera or Medroxyprogestone).. Good luck!
If you got a negative urine test and a negative blood test than you are not pregnant. Unless you have had unprotected sex within the last week or so and its just too early for it to show positive. But if its been 73 days than no. You should schedule an appointment with your doctors and see if they can give you something to help jump start your period.
If you're getting negative pregnancy test and a negative blood test. you're prob not pregnant. you should see a doctor something might be wrong with you're health. good luck