var hitleft = 0;
...

if(mouse_left==1 && hitleft ==0)
{
	hitleft = 1;
	ates_per = 0;
   	while(ates_per<99)
	{
		ent_animate(me,"5atak",ates_per,ANM_CYCLE);
   			ates_per += 1*time_step;
		wait(1);
	}
	ates_per = 100;
	ent_animate(me,"5atak",ates_per,ANM_CYCLE);
	hitleft = 0;
}