I'm four days late for my period. i took a pregnant test two days ago and negative. my last period was march 7.

Not Pregnant: You are probably not pregnant then and have missed a period. You did not ask a question. But, this is one of the most common reasons for patients to visit their doctor. Most missed periods are due to extremes such as dieting, stress, hormones, extreme exercise, obesity. They usually resolve within one month. If you feel you could be pregnant due to sex during ovulation then test again.