Monk class

Hello

So, i am interested in the class Monk, i like the type (fighting with fists) but the problem is he is too damn weak... for example with 18 constitution he has only 10 hp, gets killed very easily and deals no damage. Logically while he ca not equip any armor, he has to have huge armor or health naturally, but he has not, he is very very weak compared to others. I can't even understand his skill: Stunning blow, when i cast it, some green light appears and that's the end. I would like to hear your opinions about this class, or share your experience. Maybe he is strong if you play correctly?

Thanks