Period after “long period”

First post 👊🏻 for the most part my cycles are on time. I use 2 apps to track and they are a day apart at predicting the next one and very accurate. So, last period was June 1 but it lasted 16 days. Yes, 16! So that’s weird. And now I’m 7/8 days late for this one. Is that to be expected after a “long period”?? Both my apps show I bled for 16 days and still predicted the next one to be on time. No I haven’t tested, yes I plan on it, I was just kind of waiting to see if it would come. I don’t feel like it’s coming and don’t feel pregnant either. Lol