Character is sliding?

I made a controller for a 2D character, but it slides, and seems to continuously add force in certain directions?

Help?

Reading input:
private bool kJmp;
private bool kUp;
private bool kDwn;
private bool Atk;
private playerController iput;
private float LR;

	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {
		iput = GetComponent<playerController> ();
		if (!kJmp) {
			kJmp = Input.GetKey (KeyCode.Space);
		} else {

			if (!kUp) {
						kUp = Input.GetKeyDown (KeyCode.W);
					}
		  else {
			if (!kDwn) {
							kDwn = Input.GetKeyDown (KeyCode.S);
						}
		  else {
			if (!Atk) {
								Atk = Input.GetKeyDown(KeyCode.X);
					}
				}
			}
		}
	}

	private void FixedUpdate () {
		LR = Input.GetAxis("Horizontal");
		iput.Move(kJmp, Atk, kUp, kDwn, LR);
			kJmp = false;
			Atk = false;
			kUp = false;
			kDwn = false;
			LR = 0.0f;

Applying the motion:

public void Move(bool Jmp, bool Atk, bool Up, bool Down,float LR) {

		if (Jmp == true && jumping == false && Grounded == true) {
			jumping = true;
			rb.AddForce (new Vector2 (0, Jump_Force));
			jumping = false;
		} 

		if (Atk == true && Grounded == true) {
			Instantiate(Slash, Player.transform.position, Quaternion.identity);
			}
	
		if (Up == true && Grounded == true) {
					print ("Looking up");
					anim.SetInteger("Look", 1);
				}
		else {
			if (Down == true && Grounded == true) {
					anim.SetInteger("Look",-1);
					}
				}

		if (LR != 0){
			rb.velocity = new Vector2 (Speed * LR, rb.velocity.y);
		if (LR < 0){
			Facing = 1;
					}
		else {
		if (LR > 0){
			Facing = -1;								
					}
		else {
		if (LR == 0){
			rb.velocity = new Vector2 (0,rb.velocity.y);
					}
		else {
		if (LR != 0  && jumping == false && Grounded == true){
					anim.SetBool("Moving",true);		
						}
					}
				}
			}
		}

		Flip ();
		Jmp = false;
		Atk = false;
		Up = false;
		Down = false;
		LR = 0.0f;
	}

You could set the velocity to 0 once no movement button is pressed / an opposing direction button is pressed. Many people say that setting the velocity directly is bad, I personally never had a problem, it’s just a matter of keeping control over the rigidbody’s behaviour.