After seeing many patients who had no appetite, especially following surgery or prolonged hospital stays, I began to realize that it takes a while for the body to adjust to the trauma of sickness.
Your body will take time to return to 'normal'. Forgive me for being a little gross here, but once your bowels begin to move, you begin to pass gas, and maybe your burp a little less, you should begin to feel hungry again.
I have seen this process take nearly 2 weeks in some patients. So if your appetite hasn't returned yet, it may be normal.
Things to look out for: nausea, vomiting (green), not passing gas, not having bowel movements. Any combination of those four things warrant an immediate return to the hospital. There may be other indications for returning to the hospital that are not listed above (i.e. having a baby, stop breathing, etc). :-)
There are some really nice people who have a website where you can sign up to speak with a real, live person who can answer your medical questions. MedHelpInPlainEnglish is the site.
Eat clear foods then advance to soft foods once you fell ready. May take a few days in between. Walk around as much as you can handle, this will help increase your appetite, gain strength and help prevent constipation