6 days late period, 2 negative tests, safe sex but he did cum in me. no signs of pregnancy?

Safe sex??: It wasn't safe sex if your partner ejaculated inside of you. You could still be pregnant. Urine pregnancy tests sometimes take longer to turn positive. Ask your doctor for a blood (serum) pregnancy test. If negative it could be a missed menses, but its probably time to see someone about birth control because this again isn't safe sex.

Can re-test in a wk: 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.