Hi I'm pretty young and pretty sexually active so I've been using this app to track my period since about the beginning of the year, and usually it works maybe a day off since its only been a couple of logs, but this time its been a week since it was scheduled and still nothing, the thing is the last time I had sex was before my period came, and it did come regularly, any advice? Could this be pregnancy or maybe my period is being irregular for another reason?