First, I want to say what happened to me is not necessarily happening to you. BUT, it's something to be aware of. I read your post and kind of froze in my tracks.
In 2007, I was pregnant with twin girls. At my 20 week ultrasound they were both measuring fine, looked beautiful and there was nothing suspected to be wrong. Three weeks later at my doctor appt, they both were measuring with stomachs that hadn't grown since the last appt, but the rest of them had. My doctor put me on modified bedrest for the next two weeks to see if that would help.
A week into bedrest I called my doctor. I didn't feel right. My urine was dark, I was bruising, and I just didn't feel like things were ok.
I was right. I was admitted to the hospital one day before I turned 24 weeks and later that night delivered my two girls. I had to since I was diagnosed with severe preeclampsia and severe HELLP syndrome. If I hadn't delivered, I would have died. Unfortunately, my little girls were too small and too premature and didn't make it.
This may not be the case with you at ALL, but please watch out for the following things...any of them...not all symptoms appear in all women...they certainly didn't with me!
-Swelling, particularly in the hands and feet
-headaches that don't go away with Tylenol
-visual disturbances, floaters, any change in vision
-high blood pressure (over 140 or over 90)
-pain underneath your right ribcage or pain that radiates to your right shoulder
-any excessive bruising
-just a feeling that things aren't right
Calling my doctor that day saved my life, even though it couldn't save my babies. In case you are wondering...the reason their stomachs were smaller (in my case) was they weren't getting the food they needed. The placenta wasn't supplying them with enough...with pre-e the veins constrict and the flow of blood and nutrients is compromised.
Anyway...I truly hope that everything goes well...watch for symptoms and call your doctor and demand to see them if you have even the slightest concern that there is something wrong with you or your baby.
I would also suggest you pay close attention to movement...any decrease in movement of your baby and you should also immediately call your doctor. I really don't want to scare you, but had to share my story...it's too important not to...
Best of wishes to you and your baby!