period late almost 3 weeks now?

Nella

i had been having unprotected sex since august and stopped in september, but we always stopped beforehe climaxed.. my period was due 19 days ago and nothing? i took two test and they were both negative, im guessing its from the stress and weight loss i have experienced due to my recent break up (happened a few days before period was due) that was very hard on me.. if you have any answers that would be great.