I'd explain to your servers and see what you can come up with. It may be eating your entree while everyone else works on the first courses, or showing up half an hour into dinner, when everyone is done with their courses.
If your surgery allows, I'd also recommend ordering several courses, and have a few bites of each. My brother in law had the stomach reduction surgery, and he can eat - albeit slowly. A cruise meal is two hours long, so you'll have plenty of time to digest a few bites of whatever is good before the next course arrives. Don't feel guilty about not finishing it! The two entree, two dessert, two appetizer club never finishes everything put in front of them!
The soups and salads (two things he does well with his surgery) are excellent. I'd agree that some of the appitizers outdid the main courses.