I got the same feeling before my first scan. Mine was only at 7w, but I wasn't even sure of how far along I was before the scan... I honestly didn't even think there would be a baby in there, and it was so small that when the screen first showed up I couldn't see anything. I almost freaked until she said "and there's your baby" he was a little shrimp looking thing just floating around inside there looking all lonely - but content and healthy! It was such a relief to know that the past month of being sick and emotional wasn't just a phantom pregnancy or something! Even though I had a pee test come up positive, I still wasn't sure. I just got my 20w scan and little dude is growing like crazy!
Trust me, you'll see your healthy little baby in there and be totally relieved and happy too see the little one peacefully chilling inside there.
Good luck!