Please many people respond

I'm 17 , been having my period since I was 11. 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 period tracker 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