AF never came to visit me?

Ok so I missed my period and I'm not sure how I would "log" that haha, I was supposed to get it earlier this month and I don't want to jump the gun and test yet, but does anybody know what to do? I mean I wrote it in my notes but I just got a notification tellin me I hadn't put anything down really for my period & it's really important that I do but...didn't get it! Help! Please and thank you =}