Hi. i think i may be pregnant. period is 3 days late. no period yet. i'm having moderate cramps & backaches, but no bleeding. should i be worried?

Take a home: pregnancy test now. Reasons for missed /late periods: low body weight, obesity, marked weight gain or loss, over-exercise such as in endurance athletes, breast-feeding, stress, illness, eating disorders (bulimia or anorexia), travel, hormone irregularities, drug use, medications (i.e., birth control) or med problem (polycystic ovary syndrome or Asherman’s syndrome. #1 reason is pregnancy.