Steve hit the nail on the head. Our eating was a way to cope with stress and other uncomfortable feelings. When you take that away, you must replace it with something else – hopefully with a healthier way to deal with stress.
I find that writing helps me get my feelings out in a constructive way. I was also seeing a therapist for a while after my surgery to work on stress management.
What do you enjoy doing? You can try reading, taking a nice bath, going for a walk, playing with your pet (if you have one), listening to music, writing in a journal, or talking to a friend in order to deal with your feelings.