Hello, what's your menarche age ? Irregular periods are quite common in early years of menarche. Eating disorders, Excessive weight gain or weight loss, extreme thinness and obesity both cause your menstrual cycle to become irregular or even to disappear,Stress or emotional problems,Hormonal problems, for example, when the thyroid malfunctions,Travel,Over-exercising all these can cause irregular periods ,consult gynaecologist once .