Late Period

Hello everyone, so my period is 4 days late, and I'm a little nervous even though I shouldn't be. About a month ago my husband and I had (kind of) unprotected sex, where he was inside me for like 30 seconds. Although I knew it was a little overboard, I look plan B just to be on the safe side. (It was like in the 29th or 30th of March) and we havent done anything like that since. I've taken 3 pregnancy tests, one was about 2 weeks after, obviously it was negative, and the other were thebday before I'm supposed to get my period, one wasn't digital, and I thought I saw a faint line, so I went and got a digital one which gave me a distinct NO-. After a month, if I was pregnant, my hormones would be through the roof unless I had some sort of difficency which I do not believe I do. My period is on the right schedule, I track the days on here and I counted since the end of my last period for a 28 day cycle because mine is pretty regular. It's been late before but not when I was this impatient for it, which I know can also cause it to be late, but all 3 tests said no. I'm feeling like crap, I have a little bit of cramping as well but that's about it, should I be worried?