Nullreference exception after creating asset

So I'm trying to create a method of creating and saving files for lip sync data as ScriptableObjects. The issue is, after creating one on the click of an editor GUI button, I get a nullreference exception when trying to assign data to it.

Here's the code. The exception is thrown at activeFile.volumeCurve.AddKey(source.time / clip.length, vol);

 void OnGUI(){
          source = (AudioSource)EditorGUILayout.ObjectField("Audio Source", source, typeof(AudioSource), true);
          clip = (AudioClip)EditorGUILayout.ObjectField("Audio Clip", clip, typeof(AudioClip), false);
          if(source && !source.isPlaying) {
              if(GUILayout.Button("Generate File")){
                 activeFile = (LipSync)ScriptableObject.CreateInstance<LipSync>();
                 activeFile.name = clip.name + " (LipSync)";
                 string assetPath = filePath +"/" + activeFile.name + ".asset";
                 AssetDatabase.CreateAsset(activeFile, assetPath);
                 AssetDatabase.Refresh();
 
                 activeFile = (LipSync)Resources.Load(assetPath);
 
                  source.clip = clip;
                  source.Play();
              }             
          }        
      }
 
      void Update(){
          if (source && source.isPlaying) {
              AnalyzeSound();
              UpdateFile();
          }
      }
 
      void AnalyzeSound()
      {
      //A whole bunch of math, basically it spits out the volume and frequency of the audio source's      output.
      }
 
      void UpdateFile(){
          float vol = Mathf.Clamp01(DbValue / 140);    //140 decibals is the loudest a human can hear without causing brain damage, so set it as the maximum because we want a 0-1 value.
          //Calculate the frequency values on a 0-1 scale. 879db is the highest value on the F1 scale, so use that as the threshold. Then do simple division for each phonetic value we want.
          float ee = Mathf.Clamp01(PitchValue > 879f? eeF2 / PitchValue : eeF1 / PitchValue);
          float oo = Mathf.Clamp01(PitchValue > 879f? ooF1 / PitchValue : ooF2 / PitchValue);
          float aa = Mathf.Clamp01(PitchValue > 879f? aaF1 /  PitchValue : aaF2 / PitchValue);
          
          activeFile.volumeCurve.AddKey(source.time / clip.length, vol);
          activeFile.eeCurve.AddKey(source.time / clip.length, ee);
          activeFile.ooCurve.AddKey(source.time / clip.length, oo);
          activeFile.aaCurve.AddKey(source.time / clip.length, aa);         
      }

If it helps, the script plays the audio and then does the calculations as it's being played (AnalyzeSound() does its calculations in realtime). I know that for some reason I'm losing the activeFile reference, but I have no clue why. I know this is kind of a dumb question, but I'm really lost on this one. Any ideas?