My son had bronchiolitis a little over a month ago. He's almost 3, so while it is rare in older childen--it does happen, he wasn't a preemie and didn't get sick much as a baby. He wasn't tested for RSV, although that is often what causes it. My experience was a bit more like Carrie's. My son was on a nebulizer for a good part of it. Extreme difficulty in breathing--I stayed up counting his respirations just making sure he was still breathing for a couple of nights. I sure hope your daughter's hasn't been THAT bad.
His ran its course in just over two weeks. He was grumpy and clingy the whole time, ate very little--just like you're talking about. I feel for you, that was not an easy time in our house--I was completely exhausted. It was also the scariest experience I've had as a mother thus far.