Last cycle 6 weeks ago, spotted once, no period since. negative hpt. took plan b feb 15 after unprotected sex with bf, no period, negative hpt results?

Possible causes: Reasons for missed / late period include: an anovulatory cycle in which no egg is released, marked v or ^ in weight; eating disorder; over-exercising (endurance athletics), stress, travel, significant illnesses, oral contraceptives ; other meds, illegal drug use, breast feeding, hormone imbalances and medical problems (i.e., pcos).