Player is falling really really slowly, character controller HELP

Unity Engine
1 
var walkingSpeedStart : float = 5;
var walkingSpeedFinal : float = 10;
var accelerationSpeed : float = 2;
var overallSpeed;
var jumpSpeed : float = 5;
var gravity : float = 5;
var slideSpeed : float = 2;

private var moveDirection : Vector3 = Vector3.zero;


var hitWallLeft : boolean = false;
var hitWallRight : boolean = false;
var hitwallLeftCount = 0;
var hitwallRightCount = 0;
var dragDownWall : boolean = true;






function Update(){

var controller: CharacterController = GetComponent(CharacterController); 

overallSpeed = Mathf.Lerp(walkingSpeedStart,walkingSpeedFinal,accelerationSpeed);
moveDirection = new Vector3(0, 0, Input.GetAxis("Horizontal"));
moveDirection = transform.TransformDirection(moveDirection);
moveDirection *= overallSpeed;


if(controller.isGrounded){
	hitwallLeftCount = 0;
	hitwallRightCount = 0;
	if(Input.GetKeyDown(KeyCode.Space)){
	moveDirection.y = jumpSpeed;
	}
}	

if(!controller.isGrounded  hitWallLeft == true  hitwallLeftCount < 1){
moveDirection.y = jumpSpeed;
hitwallLeftCount += 1; 
hitwallRightCount -= 1;
}

if(hitwallLeftCount >= 1){
hitwallLeft = false;
}

if(!controller.isGrounded  hitWallRight == true  hitwallRightCount < 1){
moveDirection.y = jumpSpeed;
hitwallRightCount += 1; 
hitwallLeftCount -= 1; 
}

if(hitwallRightCount >= 1){
hitwallRight = false;
}

if(dragDownWall == true  !controller.isGrounded){
moveDirection.y -= slideSpeed * Time.deltaTime;
}

if(dragDownWall == true  controller.isGrounded){

}

controller.Move(moveDirection * Time.deltaTime);
moveDirection.y -= gravity * Time.deltaTime;
}

The player falls so slowly and not sure why

2

Try increasing the gravity.

3

Also your last line of code is doing nothing, you change the moveDirection.y, and at the beginning of the next frame you set it to 0, so you are not using it, try to change the order of your 2 last lines.