What could it mean if you should have been 7 weeks pregnant but measured 5 and a half weeks on the ultrasound?

Ultrasounds are pretty ahrd to fight with. If they say your 5 and a half weeks, most likely, you're 5 and half weeks. Maybe sit down and figure out why you think your 7? == Answer== I am so sorry you have to go through this confusing time right now. You could have ovulated later than you thought, your date of your last menstrual period could be off or the embryo is not growing like it should be. One thing you can do is go back for another ultrasound about a week later to monitor the growth. good luck.