Confused by Pregnancy Calculators: How Many Weeks Pregnant Am?

Hello everyone, I got a BFP yesterday morning. My boyfriend and I were only able to sleep together between November 6 and 10 this cycle. My period lasted from October 26 - November 1. I logged my pregnancy in Flo and they are telling me I'm on week 5. I looked this up and apparently weeks are counted from the first day of the last period, not the date of conception. So when women on here say "I'm X weeks along", they're counting from the first day of their last period? So would I tell people I'm 5 weeks pregnant, even though I have not been pregnant that long? I read that women should have their first doctor visit at 6-12 weeks. Is that counting from conception? Or do I need to set up an appointment ASAP?