Is my HUGE preggers cow okay?

Many of you have been following our "cattle saga" and know that we recently got some bred Longhorns after 25 years of not having any cattle. Four calves are on the ground now ~ no calving problems with them. But we lost one cow and suspect it was calving problems, but don't know for sure ~ she was awful small to be calving. Now we're nervous. Does this look normal to y'all? http://davesgarden.com/journal/si/9917.html Those pics were taken nine days ago and still no calf AND no udder enlargement! We've been checking on her three and four times a day and have the vet on speed dial on the home phone and cell phone. We bought her bred, so don't know what she was bred with, but would the biggest breed of bull you can think of make a calf that big? The cow is about 12 or 13 hands high.

I hope it ends up that she has twins and all this worry is for nothing.