Hey, A.!
You're not alone. I had 2 perfect pregnancies and two perfect babies and thought I was done. Both times I got nothing but positive reports throughout and amnios to reassure there was no down syndrome etc.
When I found out I was pregnant the third time (now) I got really really scared. We don't have insurance, so I do it with no epidural to save cost-I was dreading going through the pain again until it made me ill. We had a billing problem (bill didn't match the quote we got for what it would cost) with the last amnio and owed $9000 on top of all other out of pocket costs, so this time I'm not getting an amnio. I'm 38 so I was fearing all the things that could be wrong and I won't know until the very end. Mainly I felt like I was pushing my luck with two perfect babies already. I had myself really freaked out and all my thoughts were negative for a while.
I'm feeling much better now. I had to refer to my inner strength and faith and my "New Earth Book" :) and remember that I was sad and scared and worried about "the future", the pain, possible problems in delivery, possible problems with the baby. What I needed to be doing was focusing on now. So I woke up everyday, breathed deep, said all my prayers of thankfulness for the beautiful life I have now, asked for peace of mind and the strength to push out the bad thoughts concerning the future. Whenever they would creep in, I would stop myself, realize what I was doing, and force myself to be thankful for the present, and have positive thoughts for the future. Like that I know I'm taking the best care of myself and the baby possible with good nutrition and sleep etc, and chances are I will be blessed with a third perfect child. If not, I know what is meant to be will be, and a blessing is on the way.
I'd rather deal with any delivery room pain and trauma when it's happening, not also dread it for 5 months before hand, so I reminded myself I'm not in any pain now.
This pregnancy sucks, I've been on bed rest on and off, my skin is horrible, my weight is bad because I haven't been at the gym like for the last two pregnancies, but I still focus on the present moment-I'm fine, I'm taking care of myself, this will pass. I'm actually much less hung up on weight and appearances this time. I bounced back twice before with lots of work-I'll do it again.
Do your best to attack your bad feelings when they come with thankfulness and joy and the belief that you have a blessing on the way. Stop and do it as many times as you have to during the day. I had to force myself all day every day for a couple of weeks, but now I'm feeling better for real, and it's no work.
Good luck, my thoughts and prayers are with you!