Haven't had a period in two months negative pregnancy test , what else could it be ?

Delayed period: Now and then, most women will have an irregular cycle, often this may be triggered by stress, travel, workload, etc. There are methods available to induce a menstrual cycle, or you could wait it out a little bit longer. However, if your periods are frequently irregular, then discuss with your PCP or GYN. Remember to protect yourself if sexually active both from STDs and pregnancy, as appropriate.