Help late period....:/

So I know plan b messes up your cycle big time but I have taken plan b many times before in the past and my periods ended up being on time that month and so forth. Fast forward last month had an accident so I took plan b asap later on that day and got my period 3 days earlier than expected. This mo which is July, I am currently 3 days late on my period.. This mo I have had unprotected sex, (quickies) for like less than a mi ute or two before putting the condom back on and my bf and I made sure to check before if he Precame or cum and even after. I'm positive he didn't because I know him... But last time I had a quickie before the condom was almost 6-6 days ago... I tested today to see and it said negative.. What could delay? Or am I pregnant? B please help