pregnant?

If you have sex can that change when you have your period? I'm two days late for mine and have had unprotected sex a few times and also protected sex (all within a few weeks). I just don't know if I should worry with a pregnancy test yet since it's only two days... my bf thinks that having sex might've changed the timing of my period.. he thinks since we "stirred things around" that my period is kind of offset. Idk.  Help!