So I got on my computer today to work on my game. I loaded up the scene. Everything in the hierarchy is GONE. What happened, and can I get it back?

EDIT:
How do I load a backup file?

It’s absolutely no substitute for keeping backups (I run mine automatically at noon every day, backed to a RAID1 NAS, the drives of which I replace annually, and even with that I get uneasy)… but here’s my auto-save script:

using UnityEngine;
using UnityEditor;

[InitializeOnLoad]
class AutoSave
{
    static AutoSave()
    {
        EditorApplication.update += Save;
    }
    
    static double nextSave = 0.0;
    static double interval = 10.0;
    
    static void Save()
    {
		if (EditorApplication.timeSinceStartup >= nextSave && !EditorApplication.isPlayingOrWillChangePlaymode && !EditorApplication.isPlaying && EditorApplication.currentScene != "") {
			nextSave = EditorApplication.timeSinceStartup + interval;
			if (System.IO.File.Exists(EditorApplication.currentScene+"-2"))
				FileUtil.ReplaceFile(EditorApplication.currentScene+"-2",EditorApplication.currentScene+"-3");
			if (System.IO.File.Exists(EditorApplication.currentScene+"-1"))
				FileUtil.ReplaceFile(EditorApplication.currentScene+"-1",EditorApplication.currentScene+"-2");
			FileUtil.ReplaceFile(EditorApplication.currentScene,EditorApplication.currentScene+"-1");
            EditorApplication.SaveScene(EditorApplication.currentScene);
            EditorApplication.SaveAssets();
			//Debug.Log("Auto-saved "+System.DateTime.Now);
        }
    }
}

Put that in Editor/AutoSave.cs and you’ll get 3 backup scenes regardless of the bugginess of a particular Unity release.