I am 6 weeks pregnant, have had brown spotting for the past 5 days. My HCG levels are a little low but doubling every 48-72 hours as normal. I went in for my first ultrasound yesterday and the tech "thinks" he saw a gestational sac but woudln't confirm it. So of course we didn't see a yolk sac or fetal pole. He said my uterus is measuring at 6 weeks but it looks like i'm only 3-4 weeks. I'm starting to worry. Has this happened to anyone else and if so, what was the outcome?