Every morning and evening are just agonizing moments for both him and me. I feel so sad to see his sad face. He just goes back to sleep when I do not open the door for him. Please help me. It is hard for some cats to adjust to an all indoor lifestyle.
Some cats never do really adapt.
Other cats adjust readily. My impression, just based on my own personal experiences is that if a cat is restless or depressed after several months then it is probably not going to adjust to an inside lifestyle. There are ways to compromise with a kitty, though. This seems to work well for many of the cats who wish to spend some time outdoors. Even though we live in a rural area, at least two or three of my clients have built these types of enclosures for their kitties.