I've had my periods for over a year, and i'm over 2 weeks late. there's no way i'm pregnet as i'm a virgin. i've gained weight and am now always tired.

Weight gain: Is a common reason for abnormal cycles. As you gain weight, your hormones become increasingly abnormal. Your body can compensate for a while but then loses that ability and periods become irregular (usually longer between menstrual bleeding). You could be Insulin resistant (pre-diabetic), which contributes to weight gain. See your gynecologist to discuss.