how do get the player unstuck

When ever I start the game the player starts in the center and wont move away from the center. Even when moved some where else the player still starts in the center
player script
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class playermovement : MonoBehaviour
    public float movespeed = 5f;

    public Rigidbody2D rb;
    public Animator animator;

    Vector2 movement;
    void Update()
        movement.x = Input.GetAxisRaw("Horizontal");
        movement.y = Input.GetAxisRaw("Vertical");

        animator.SetFloat("Horizontal", movement.x);
        animator.SetFloat("Vertical", movement.y);
        animator.SetFloat("Speed", movement.magnitude);

    private void FixedUpdate()
        rb.MovePosition(rb.position = movement * movespeed * Time.fixedDeltaTime);

That is not the correct thing to do. Maybe you want this

rb.MovePosition(rb.position + movement * movespeed * Time.fixedDeltaTime);

Another way is to use rb.AddForce()