What should my diet consist of after being released from the hospital for appendicitis?

For something like this you really should consult with your doctor. You should have been given explicit follow up instructions as to what you can eat, what problems to look for, and what type of activity level you can keep. Call the hospital if you did not receive this very important information and insist you receive it in writing either via fax, email, or have someone bring it to you. Why in writing? So you have no question and you have some recourse should something go wrong that was not your doing.