How to make this actor to move?

Unity Engine
1 
using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;

public class ballCtrl : MonoBehaviour
{
    private bool isRightPressed = false;
    private bool isLeftPressed = false;

    public bool isCrashed = false;

    private Rigidbody2D rb;
    public float sensivity;

    void Start () {
        rb = GetComponent<Rigidbody2D> ();
    }

    void Update () {
        if (!isRightPressed && !isLeftPressed) {
            //Debug.Log ("What the...?");
            return;
        } else if (isLeftPressed) {

            //Left
            rb.AddForce (Vector2.left * Time.deltaTime * sensivity);
            Debug.Log ("Left Go");

        } else {

            //Right
            rb.AddForce (Vector2.right * Time.deltaTime * sensivity);
            Debug.Log ("Right Go");
        }
    }

    public void LeftDown(){
        isLeftPressed = true;
        Debug.Log ("Left Down");
    }

    public void LeftUp(){
        isLeftPressed = false;
        Debug.Log ("Left Up");
    }

    public void RightDown(){
        isRightPressed = true;
        Debug.Log ("Right Down");
    }

    public void RightUp(){
        isRightPressed = false;
        Debug.Log ("Right Up");
    }
}

How to make this move?? Actor that this script connected aren’t moving.

public float sensivity;

is not 0, and also I checked that these functions are called.
(LeftDown, LeftUp, RightDown, RightUp)

PLZ HELP

2

Why create a new function for each direction? Try it

rb.velocity = new Vector2 (Input.GetAxis ("Horizontal") * 12f, rb.velocity.y);

Do you need another jump? I do it this way

rb.AddForce (transform.up * 14f, ForceMode2D.Impulse);