My period is 4days late now and iv been experiencing minor pains in my tummy, no energy, sore breasts and constantly tired. should i be worried or?

May do a preg. test: In a woman with regular periods, some causes of a late period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (like birth control pills), hormonal imbalances, etc… Seeing a doctor is a good idea if symptoms are persistent, recurring, or worrisome. Pregnancy is the common cause of a missed period, if sexually active.