rigidbody2D.velocity returns zero values

Hello,

I'm trying to make a 2D-platformer using the 2D tools in unity 4.3.4. I have successfully created a player object and a level, I can walk to the left and right etc, but I am having the hardest time making my character jump. One of the problems I'm having is that when I get rigidbody2D.velocity.x or y, the y has a negative value when the game starts (character spawns in the air), but after a few frames it changes to 0, even while falling. The same applies to the x of velocity, when I start moving my character it will shortly display a value, but then changes back to 0 even while moving.

Also my jumping is really buggy for some reason, no matter what I set the jumpForce to beyond 3000, it will never go beyond a certain height... My project's gravity is set to 30.

This is my player's object script:

 using UnityEngine;
 using System.Collections;
 using System;
 using System.Diagnostics;
 
 [RequireComponent(typeof(Animator))]
 public class Player : MonoBehaviour {
 
     const float maxSpeed = 1000f;
     const float jumpForce = 2000f;
 
     private Animator animator;
 
     bool onGround = false;
     public Transform GroundCheck;
     public LayerMask GroundLayers;
     const float groundCheckRadius = 1f;
   
     bool facingLeft = false;
        
     void Start () 
     {        
         animator = GetComponent<Animator>();
     }
            
     void Update()
     {
         bool oldOnGround = onGround;
         onGround = Physics2D.OverlapCircle(GroundCheck.position, groundCheckRadius, GroundLayers);
         if (onGround != oldOnGround)
             animator.SetBool("Ground", onGround);
     }
 
     void FixedUpdate()
     {
         float inputX = Input.GetAxis("Horizontal");
         float inputY = Input.GetAxis("Vertical");
         animator.SetFloat("hSpeed", Math.Abs(inputX));
         animator.SetFloat("vSpeed", rigidbody2D.velocity.y);
 
         float speedX = inputX * maxSpeed;
         rigidbody2D.AddForce(Vector2.right * speedX);
       
         print("x: " + rigidbody2D.velocity.x + "y: " + rigidbody2D.velocity.y);
 
         if (onGround && inputY > 0)
             rigidbody2D.AddForce(Vector2.up * jumpForce);        
 
         if ((inputX < 0 && !facingLeft) || (inputX > 0 && facingLeft))
             Flip();
     }
 
     void Flip()
     {
         // Switch the way the player is labelled as facing.
         facingLeft = !facingLeft;
 
         // Multiply the player's x local scale by -1.
         Vector3 theScale = transform.localScale;
         theScale.x *= -1;
         transform.localScale = theScale;
     }
 
     void OnCollisionEnter2D(Collision2D info)
     {
 
     }
 
     void OnCollisionExit2D(Collision2D info)
     {
 
     }
 }