Delete all your units and build walls. If yu're playing on hard/very hard the walls are crucial, cus most rebel bands are all horse archer in that area, and they'll usually not be able to attack you. After you've done that and more or less secured yourself you can concentrate on building roads/markets etc, you have 4 cities, which is more than most barbarians, so if you build a farm and a trader in all of them plus link them with roads, you'll be getting a tidy income. Dont forget to set up trade agreements with armenia, parthia and the seleucids.