NullReferenceException

I know there have been many questions on this before, but each question has had completely different code to mine, and I thought I should ask.

I have started making a player job script, and it works, but whenever I build the project in order to test the multiplayer, it comes up with the error constantly, and it fills up the log box within seconds.

Here is my code:

 using UnityEngine;
 using System.Collections;
 
 public class PlayerJob : MonoBehaviour {
     
     //0 = Unenmployed
     //1 = 
     
     public int Job;
     public Date date;
     public Money money;
     public bool payday;
     
     void Start()
     {
         money.money = 0;
         payday = true;
         Job = 1;
     }
     
     void Update()
     {
         if(Job == 0&&date.day == 4&&payday == (true))
         {
             money.money = money.money+0;
             payday = false;
         }
             if(Job == 1&&date.day == 4&&payday == true)
         {
             money.money = money.money+100f;
             payday = false;
         }
         
         if(date.day == 5&&payday == (false))
         {
             payday = true;
         }
     }
     
     
 
 }