What to do if i didn't get my periods since 7 may, im 38, hve no kids, pls. advice?

Possible reasons: Missed/late period: low body wt, obesity, weight ^ or v, ^exercise, endurance athletics, breast-feeding, stress, illness, eating disorders (bulimia or anorexia), anovulatory cycle (no egg released), travel, perimenopause, just starting menstruation, hormone irregularities, drug use, meds (i.e., birth control) or medical problems (i.e., polycystic ovary syndrome). #1 reason is pregnancy. Gyn eval.