Possibility of another blighted ovum?

Yes. It's totally normal to feel scared especially after you've had a miscarriage in the past. I was terrified I was going to have a miscarriage with my daughter (who is now 2) and then actually had one between her and my son, who is now 3 months old. I was very scared for the first 12 weeks about another miscarriage and then after that was over I moved on to worry about something else. It's just important to remember that MANY women have miscarriages and that they are a surprisingly normal way of your body dealing with a pregnancy that is not healthy. I know many women who have had miscarriages due to blighted ovums and continue to have many kids afterwards. Try to relax...I'm sure you'll feel much better after the ultrasound.