Namespace Errors

I am extremely new to C# and scripting in general. I am getting three errors in my script: Assets/Scripts/PlayerHealth.cs(25,14): error CS0116: A namespace can only contain types and namespace declarations

Assets/Scripts/PlayerHealth.cs(28,14): error CS0116: A namespace can only contain types and namespace declarations

Assets/Scripts/PlayerHealth.cs(31,21): error CS0116: A namespace can only contain types and namespace declarations

I have absolutely no clue what they mean or how to fix them. My full script is:

 using UnityEngine;
 using System.Collections;
 
 public class PlayerHealth : MonoBehaviour {
     public int maxHealth = 100;
     public int curHealth = 100;
 
     public float healthBarLength;
 
 
     void Start() {
         
         healthBarLength = (Screen.width / 1);
 
         InvokeRepeating("HealthDrop", 9f, 9f);
     }
     
     void HealthDrop() {
         curHealth -= 1;
     }
     }
     
     
 
     void Update () {
         AdjustCurrentHealth (0);
     }
     void OnGUI() {
                 GUI.Box (new Rect (4, 4, healthBarLength, 8), curHealth + "/" + maxHealth);
         }
     public void AdjustCurrentHealth(int adj) {
         curHealth += adj;
 
         if(curHealth < 0)
                         curHealth = 0;
 
         if(curHealth > maxHealth)
                         curHealth = maxHealth;
 
         if (maxHealth < 1)
                         maxHealth = 1;
 
         healthBarLength = (Screen.width / 1) * (curHealth / (float)maxHealth);
     }

Thank you for your time and any help.