Period confusion

Laura

So my period normally occurs towards the end of the month, yet it was early last month (June 13-18). Both <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> & Flo apps say I’m 2-4 days late and although I had unprotected sex two weeks ago, I’ve had two negative pregnancy tests since. Could it be that my period may just start sometime next week like it’s been in the past?