I might be pregnant. Need advice.

Im 18 and a senior in highschool. Me and my boyfriend have been together for a little over a year. I live with him in his mother because of family issues I was having. We dont sleep in the same room because his mother wont allow it. And I completely comply with any of her house laws because of the respect i have for her. Anyway...I been having this weird feeling in my stomach lately and now my period is three days late. Has anyone delt with teen pregnancy? Im just scared to see how this plays out. Iknow my family and David's family is going to be very disappointed.