Hi Mitch, I was really nervous before my first ultrasound too. I had barely any symptoms so I was worried that I would be told that I wasn't pregnant or that the baby had stopped so I know how you're feeling. I think its normal to have no symptoms - lots of people don't have noticable symptoms.
I don't really have any ideas on how to stop yourself from stressing other than to suggest that you try and keep yourself busy. Make you could go on a date with your DH and/or your girlfriends or go for a day trip over the weekend.