My period is a week late. i took a pregnancy test last night and it was negative. this is supposed to be my 3rd period since coming off the pill. should i go see a doctor?

It happens sometimes: Home urine tests are very accurate by 3 weeks after sex (a positive test result may happen by 1.5 weeks after sex, but a negative result may be a false negative if tested too soon after sex). So, a woman with a negative result can recheck it a week later. If still negative, she is not pregnant. If she misses a second period a month later and is still test negative, she can chat with her doctor.