The most important things in your situation are to keep a positive outlook. People who get angry and depressed are more likely to gain weight and lose their health. So the key is to focus on good things in life or things that you like. That might sound hard, but part of that is accepting the fact that we can't undo what has happened, but if we hang in there, we can make our lives better. For some people, it just takes some time and healing.
Since you are rather immobile, you are really going to have to watch what you eat and drink. It's always possible for people to lose weight if they change their eating habits. Some just have to be more extreme then others so they like to believe it won't help. So I think you should try to put together a list of healthy foods to eat. Do you cook or do you have someone to cook for you? You should stay away from fast food if possible. Drink LOTS of water instead of sugary drinks or diet drinks.
What you eat/drink and how much will have a big impact on your weight. So if you can't exercize, at least concider those things. Keep up with the physical therapy and always let your doctor know about these feelings you are having.
Good luck to you hon!!