gravity+jump problem unity 3d

Hello. I have the following problem: Gravity instead of pulling the player down pulls him up and the player does not jump when i press the G button. Please help solve the problem and fix it.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 using UnityEngine.SceneManagement;
 
 public class FPSInput : MonoBehaviour
 {
 
     private CharacterController charcon;
     public float speed = 6f;
     public float gravity = 9.81f;
     public float jumpForce = 100f;
 
     private Vector3 movement;
 
 
     void Start()
     {
         movement = Vector3.zero;
         charcon = GetComponent < CharacterController > ();
     }
 
     void Update()
     {
 
         Movement();
     }
 
     void Movement()
     {
 
         movement = new Vector3(Input.GetAxis("Horizontal"), 0, Input.GetAxis("Vertical"));
 
         movement *= speed;
 
         if (Input.GetKeyDown(KeyCode.G))
         {
             movement.y *= jumpForce;
         }
         else
         {
             movement.y -= gravity;
         }
         charcon.Move(movement * Time.deltaTime);
     }
 }