I just got back from Bella's regular vet. He looked at her and everything and said he doesn't think anything is wrong with her back at all. He thinks she ate or got into something that made her sick. He said that with the rain we have had recently, there have been some wild mushrooms that have made a number of dogs sick in the past week or two. He thinks her weakness in her hind legs was a result of her having intense pain in her stomach from some sort of toxin or food poisoning from something she ate. He thinks the medications she is on will clear everything up in a few days and that she will be back to normal. He said the reason I probably didn't understand the other vet's explanation of the x-ray very well is that she didn't actually find anything that supported her theory of degenerative disk disease. He told me that if her back was really injured, she would still have signs of pain or limping today.
I really really want to believe that her regular vet is right and that she is going to be totally fine and back to normal in a few days. I do trust him and she does seem soooo much better today. But, I don't want to make a mistake and be wrong and have her get worse. For right now, I am thinking I will continue to keep her confined to the crate and taking it easy for a while longer. Keep her on all the medicines like both vets have recommended. I guess I can just watch her closely and seek out a specialist if she regresses even the slightest bit.