Jane, this is so sad. I can't believe cancer can kill a bunny so young of age. I mean, unless it is genes related from his parent, it's hard to imagine what could cause such cancer to strike Lord Lopsley, as I always thought the first few years of a rabbit's life is their strongest year. This is so shocking. I'm so sorry this happened to Lord Lopsley.
If you are too upset, take a deep breath, drink some hot tea, and call some of your friends to come by to keep you company for a while.