I'm 17 , my period was early December. Had intercourse around December 23-27th 3x with a condom he pulled out and came. Got my period January 2nd. Cramping heavy on first day. Lasted about 4 days. I checked my <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period tracker</a> and it says I'm late 3-5days. 3 on this app. I'm scared because I was suppose to have my period apparently and i havent. I've been having symptoms too like a sharp knife in my boobs and etc. I'm super stressed.