This may be a silly question but...

On my Glow calendar, I'm struggling to understand my percentage of pregnancy? 
​The easiest way to explain this question is for example yesterday I had a 7.8% chance of pregnancy and I had unprotected sex. So does this include the fact that they say sperm lives in the body for upto 7 days? Because if so then in 5 days I have a 22% chance. This sounds really confusing I know but basically is there a chance I could be pregnant?