I'm actually feeling really good about this baby's health. I'm a bit concerned about labor and delivery; this is my third pregnancy, my third child and I have yet to have a normal, healthy delivery. I can say, however, that I was *absolutely correct* with my first two children about what would happen, and that my biggest mistake with BeanBean was that I did not listen to my body and tell that evil witch doctor to f*** off. So I'm pretty confident that I'll know what's going on with this one.
When I have an irrational fear, I try to look at it objectively and figure out where it's coming from. Most of my fears this pregnancy, the overwhelming majority of them, obviously stem from money problems, so it's easy for me to deal with it and move on. In terms of delivery, this time I'm hoping to have the baby at home ("accidentally"

); my greatest fear is that something will go wrong and we won't have enough gas in the car to get to the hospital in time (there's no way in hell we can afford an ambulance!). I know that this is a general fear of money problems, rather than a fear about the birth itself, so I can deal with it.
When I worried about the baby's health (briefly), I didn't feel too concerned, just vaguely uncomfortable. I have had nightmares about other things relating to my older children, but not so much about the baby; these fears are all perfectly normal. Pregnancy makes your mind work in mysterious ways. If you're really worried, like, unable to function because you spend so much energy worrying and being afraid, try to find out what the root of your fear is. If an ultrasound will help you get some peace of mind,
do it; being constantly terrified (not just vaguely worried, disquieted, or bothered but actually afraid) that something is wrong with your baby for nine months has been definately proven to be detrimental to babies in utero, while one or two ultrasounds during a pregnancy haven't been proven to cause damage. I think it's much more dangerous for your babe to have a mamma who's constantly terrified than to have an ultrasound and gain some peace of mind and perspective on the whole situation.