Could I still be pregnant I'm 5days late and I took 2 tests a day ago and both were negative and I'm always regular?

Can retest next week. 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.