Help!! Missed period ?

So i just started my birth control this month I am over a week late on my period and don't know if I am pregnant. My boyfriend and I have had sex several times this month but every time he wears a condom I missed my birth control once this month a few weeks ago but took it the next day the only time we didn't wear protection was when we were jus fooling around his penis went in only a little for literally 10 seconds. But again I am on the pill and this happened on my last week of the first pack. I just want to know what is wrong why I am so late I have also recently started running everyday also I am very stressed especially this month I just graduated from highschool and this so very stressed someone please help!!! Also I don't seem tiers I'm not feeling sick or any of that I have some cramps and break