I would love to trade places with you. I am also preggo with #3 and I'm 28 weeks and still battling morning sickness. Thankfully it's not as bad as it was in the beginning, but no fun none the less.
I understand your concern as the same thing happened to a friend of mine. If you can't get in to see if your midwife will check on the baby, you can always call your local women's resource center. They usually offer free ultrasounds for peace of mind. :o)