i dont know if you will get back to read this since it is a late post but!!
during two of my three pregnancies i developed carpal tunnel syndrome from nerve impingment from fluid retention and from sleeping badly on my wrists. i know it might sound silly but my doctor told me to wear wrist braces (the large over the thumb jobbies that you can get at your local pharmacy aisle at your "super store") and that helped a quite a bit...
my almost 5 month old is almost 20 lbs so i have been having a harder time with him. my first son grew alot slower... but the wrist braces are worth a try and not too expensive if this is still a problem for you.
all else fails call the doctor!
they might have some more tricks up their sleeves!