17 days late?!

Ok ladies i need some help. Im 17 days late and my last period was on Oct 17. I need help figuring out whats going on. Ive got PMS symptoms. Ive got acne, back pains, cramps and i have watery discharge. Im not sure whats going on. Im not pregnant because the Tests have came out negative and ive been cramping for almost 2 weeks now and still no period. Help?!