My Period Is Late By About A Week

I am a 20 year old girl and a virgin, but my period is late by about a week. I recently started seeing someone, and though we have not had sex, we have mutually masturbated (always ladies first) several times. Whenever we do, his hands are always clean and I will always thoroughly wash my hands. Last week, he touched me after I had touched him--but this was after he had showered, washed his hands with soap and water, and after a period of about 20 minutes. My period is about a week late. I have been on break from school since before Christmas, and during that period, my sleep habits, stress levels, and diet has changed. I am also not living with my roommate, who is on birth control for hormones and whose hormone levels probably have had some effect on me. I know that this question sounds ignorant. I'm just a little panicked. I cannot think of any way in which I could have gotten pregnant. But, my period is also MIA. Answers?