Everytime I get attacked I have so many losses but the attacker like almost nothing what am I doing..

For every attack there is a battle report in your mail. Have a look and see what the attacker has for troops / heroes. Any well upgraded heroes or higher level troops will mean that they can defeat you easily. If the enemy is a raider or has researched a lot then they will also have an advantage. There are many buildings, research items, parts and other items in the game that give bonuses to attack and defense. These will all help be stronger.