I've noticed this happens during the winter. They are used to hibernating during this time of year. The only problem with this from what I've found is that the frogs don't eat after winter sometimes which leads to their death. It sounds like your toad is interested in eating a bit so I'm not sure if her wanting to go into hibernation is the cause. I'm no expert but it's just an idea. Many of my frogs who do ths don't do it the following winter which makes things a lot less stressful.