Please help. I experienced some light spotting Thursday night. It got worse early Friday morning so I went to the hospital where they preformed an ultrasound. I was told they didn't see anything at all but my hcg levels were around 500+ and that placed me at around 4 weeks. The spotting has stopped after a day and a half. Does the ultrasound go by the gestational age or the fetal age of the baby? I'm scared that they couldn't see anything. Glow tells me I'm 5 weeks and 4 days, is it normal to not see at least the sac?