Help a gal out

My period is 8 days late and I’m unsure as to why. Me and my boyfriend have had sex and we use condoms and he pulls out simultaneously. There have been no malfunctions of the condoms we are aware of. It was meant to come on the 19th but still hasn’t shown. I have started back to school and my part time job after Christmas, as well as that me and my boyfriend had a big fight on the 18th which caused me to non stop cry for a day straight (we rarely fight). I haven’t had much symptoms but my boobs were tender yesterday and I had some faint cramping, maybe PMS? Just so unsure. I mean my cycles can be irregular as I’m only 18 years old but they could only fluctuate by maybe 3 days or so.