7 weeks and 3 days

Hi everyone so I thought I was 3 weeks pregnant but it’s my first pregnancy I didn’t realise dr’s count from the first day of your last period!!! According to the Gp I’m 7 weeks 3 days but really I think I conceived mid April which would make me only 5 weeks...

Anyone confused by how medicine measures it??? She wants me to take a flu shot but I really don’t want to as a lot of people I know got really sick with the flu shot

Any thoughts