I didn't have my period since 3 month, i'm a bit depressed/stressed out, could this be related?!

Possibly.Time to see: Gyn & psych.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 med problems (i.e., polycystic ovary syndrome). #1 reason is pregnancy.