
If your girl is so obviously well in herself, I wouldn't worry too much. I'm used to whelping toy size bitches and, for all the worry warts who scare you about only one puppy (fingers x'd here), I've never had a problem.
You are used to dogs - you would know if it was a dead puppy - they feel totally different. One of my girls worried me 2 or 3 years ago when I could feel (what I thought) was one huge puppy. I couldn't feel it moving though, and assumed that it was packed too tight to have enough room.
The day before she whelped, I actually felt it moving down - to leave enough room for the one under the ribcage to slot into place! I won't have my toy breeds scanned, they get too stressed, and I'm worried that they will go into labour too early. By the way, I bought a stethoscope, and the vet asked how I got on with it. I told him that I may just as well have used a tube of smarties for all I could make out!
You know your own bitch, and I feel sure that you would know if anything was not right. Good Luck :-)