I m late on my period and so scared?

See below: Get a home pregnancy test. They'll be positive by the time your next period would start. If it's negative, repeat in 1 week.

If you are sexually: active than go ahead and take a pregnancy test now. (repeat in 7 days if negative) 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