Sex/fertile days/pregnancy

So my bf lives out of state and I visited him the 17-19th. Of course we sad sex everyday I was there and twice some days. We never use protection bc we don’t care if we have a kid together. We’re both at the age where we wouldn’t mind having one. Anyways, my fertile window didn’t start until the 20th but I’m now 2 days late on my period. Supposed to start December 8th and have no signs or symptoms of it coming or any signs of being pregnant either. I’m confused. I have been very tired lately but i think that’s bc of work. What do y’all think this is? Am I just late or is there a chance I could be pregnant somehow? Should I wait a few more days? Thanks