Pizza and pasta really aren't helping your situation.  As you said, you know that meat, fish, fruits, and vegetables are the best foods.  If you want to get healthier, you have to eat better - that's just reality.

It sounds like you are ready for a change.  You might want to start by just mixing in some fruits and vegetables each day.  It's likely that your tastes will start to change.  Just take your time and make some gradual changes.  Buy some different foods at the grocery and try to work them in.  Snack on apples, bananas, carrots, that sort of thing.

Good luck!