There are two reasons for having a negative pregnancy test and missing your period: You did not ovulate anovulation or you did too early pregnancy testing.
When you miss your period you have 'amenorrhea'.
There are two major reasons for having amenorrhea and not getting your period but having a negative pregnancy test:
If you are pregnant then your pregnancy test is usually positive within one week after missing a period. After ovulation is takes on average 9 days for implantation to happen, and then again 4-5 days for the urine pregnancy test to become positive.
You should talk to your doctor and find out what happened.