I went to the doctors today to ask them why i haven't started my period they did a urine test for pregnancy and it was negative? why no period yet?

Some thoughts...: 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 (no period for several months), recurring, or worrisome.