Pregnant or stressed?

I’m 45 days late for my period, and 78 days since my last period. I took 3 pregnancy tests when I was 20 days late and they all said negative.

I’m thinking about stress too because my boyfriend and I broke up, we moved in together in Tulsa in July, and then I moved back to Arkansas ultimately ending our relationship about a week ago. I have hives and a cold sore (I get them when I’m stressed), but not symptoms of period or pregnancy. So that’s why I’m thinking it’s stress.

But how long has anyone gone before they knew they were pregnancy?