The last time i had sex was about a week ago. My boyfriend and I had unprotected sex but he pulled out like 15 secs before he cam. IS there a chance i could be preg. ?  my period started last month on the 28th. and its now the 1st. i m a couple days late but idk if its cause im worrying about it.  Should i be concerned? How long should i wait to get a pregnancy test?