Lack of the menstrual period is the first sign of pregnancy, but lack of menstruation does not always indicate pregnancy. Other conditions such as an ovarian cyst, hypogonadism, menopause… can also cause lack of a period. Cramps and spotting are not signs of pregnancy. They can be signs of a complicated pregnancy if you were already pregnant, which was not in your case. The only secure sign of pregnancy is a positive pregnancy test and your pregnancy test was negative. You can consult a gynecologist to identify the reason for your period delay. A vaginal examination, PAP-test and ultrasound scan will probably be requested.