Late period, the waiting game.

My periods are very regular, I always get it on 22 or 23. I haven't had no signs of it just little cramping here or there. I had unprotected sex on my fertility week more then once and he came in me. I'm about week late now. I don't have any symptoms. I've taken a dollar store strip pt and it came out negative. Went to a clinic Friday and came back negative. The doctor did tell me if I don't get it in another week or 2 to back and test again because maybe my levels are not high enough to show up. I do drink and smoke weed every weekend or so. I do what a every 20 year does goes to school and work. My boyfriend told me to stop partying cause he's afraid if I really am I'm harming the baby. Now he got me paranoid.  Should I keep testing or just wait it out? Has it happened to any ladies before?