Had my first prenatal visit yesterday and...

My first prenatal visit was yesterday. I went to the dr thinking I was 6wks and 1day. But found out I'm a week behind. They did a ultrasound and was to early to see a baby.. but the tech did see 2 gestational sacs. Dr told me to prepare for twins cause that's what it looks like. I go back in 2 weeks for another ultrasound. I'm told babies will be visible by then and will even see their little hearts flickering. I'm very happym but stillnin shock.