Is there any way to get back a city that you lost while you were not playing or did i just waste a month playing this game?
I understand that Grepolis can be very frustrating, especially if you lose a city you have been working on. There are a few ways to protect yourself against "big" players.
1) Find an alliance that helps you: It is extremely hard to play against other players by yourself. It is essential to have a good alliance that supports your towns with troops and backs you up when other players attack you. This way many small players can stand up against bigger enemies. It is also very beneficial to learn proper methods of defending to improve your chances against attackers.
2) Try playing on a recently opened world: This allows you to play the game against people who did not have time to build up huge armies, as it is extremely difficult to play on worlds that are a few months old.