6 days late. 4 test neg. all symptoms. major cramps and pains in stomache and tail bone. what can this be?

Infection: Cramping is not a symptom of early pregnancy. It is a symptom of infection or premenstrual situations. You very well may have a urinary tract infection.

Late menses: Reasons for missed/late periods: low body weight, obesity, marked weight ^ or v, over-exercise, endurance athletics, breast-feeding, ^ stress, illness, eating disorders (bulimia or anorexia), anovulatory cycle (no egg released), travel, hormone irregularities, drug use, meds (i.e., birth control) or medical problems (i.e. PCOS). #1 reason is pregnancy.