It may be hard to suggest solution now, as you already suffered significant damage, but the #1 step you have to do is to max out your towers! If you had 20-30 towers all maxed out along with Collectivism bonus, attackers would think twice before touching you. Unfortunately despite the fact that this receipt is simple and straightforward, a lot of people postpone building towers until it is too late.
If you have been attacked by a multiple players (alliance), unfortunately your defences are limited, especially, if they are significantly more developed than you. In this case you can only defend with the help of your own alliance.
If you are in a bad situation with mutliple attacks coming from all sides, you might sacrifice your less important towns and concentrate on the most important one - max out wall and towers in it and concentrate all your army in it. Apply defensive item on that town. Have your allies send all their reinforcements in that town only by the time your truice ends. Members of your alliance who are the most distant from you should send their whole army, and not just a couple of units.
In the rest of the towns don't bother building towers, without army they will be wiped by rams easily. Better build houses/cottages there until your building percentage will reach 50% - the houses are harder to destroy and will help you building towers on the next truce.
Your current short term goal is to survive with minimum damage between truces with the helm of your alliance. Your long term goal is to have maxed wall and towers in all towns and maxed army with catacombs in place. And by saying "maxed out wall and towers" I mean wall or fortified wall level 9 or 10 and 20-30 level 5 towers depends on your research status.
People, NEVER FORGET ABOUT YOUR DEFENSE! No matter how peaceful you are or how good your diplomacy is. Build towers in-between your regular buildings CONSTANTLY. I cannot emphasize that hard enough. Do not complain if you do not do that, because it is not the game's fault then, it is yours!