Menstruation not coming, negative pregnancy te?

Likely missed it: It is not uncommon for even the most 'regular' cycling females to miss an occasional period. If worried about pregnancy, can check a second home pregnancy test at least one week after first--if also negative, then just missed a cycle--nothing to worry about unless becomes a pattern, then see your gyn.

Amennorhea: Pregnancy is certainly the most common reason for a missed period when sexually active. An anovulatory cycle (your ovary just does not release an egg that month), thyroid conditions, rapid weight fluctuations, extreme exercise, stress, etc. Are all other causes that may be possible. If you keep having sex unprotected, check preganany tests, otherwise if you miss your next one too, see dr. For eval.

Negative HPT: 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). Pregnancy is #1 reason.