Pmsing for a week, no period, not sexually active. i've been stressed out with school and i lost 10 pounds could this be why my period is a week late?

Yes: Both stress and rapid weight loss can cause your period to be late or for you to miss a period. Have you talked to your parents about how stressed you feel about school? To address stress: talk about feelings ; address problems. Don't avoid them. Aim for 7.5 - 8 hours of sleep/ night. Daily physical activity is optimal in a green space. Eat healthfully. Cut out junk carbs or caffeine.