Period 2 weeks late and very light with some brown blood. no sex since last period. have irregular period once in while. is it normal?

Yes: Our stress and anxiety level, also our diet and exercise level can affect our hormones. Hormonal variation can affect your monthly flow.

Late + light period: Reasons for 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.