How many days is it normal for a period to be late??

My periods pretty irregular. One mo it's early by 3

Days and mo after early by 1'day.. This mo I missed it by 3 days.. I just started my new job and been crying and depressed for 2 weeks and plus 7days ago which is the 18th before the 20th (which is expected period) me and boo did unprotected sex for a good minute then put on the condom.. Idk what's the cause..

Stress

Or the unprotected sex.. In the past

We have raw sex one two days before the period and we ended up having it on time.. Is

It due to

Stress?? Or? I tested

And it said negative.. Been having minor cramps and Breast pain that comes and goes .. Minor headache as wel.. It's been a week and trsted negative.. Not really any pain or anything.