Odd behavior with project 3.5

I worked on this project a few weeks ago and everything was completely fine. I just reopened it to resume work on it and the project is really screwed up. For one, when I open any of the folders in my project hierarchy every single folder in my project hierarchy opens at the same time. When i try and close one folder, all of the folders close. I also can't add a folder or file of any kind to my project. When I try and add a folder, for example, i get the following:

NullReferenceException: Object reference not set to an instance of an object UnityEditor.BaseProjectWindow.BeginPreimportedNameEditing (Int32 instanceID, EndAction endAction, System.String pathName, UnityEngine.Texture2D icon, System.String resourceFile) UnityEditor.ProjectWindowUtil.StartNameEditingIfProjectWindowExists (Int32 instanceID, EndAction endAction, System.String pathName, UnityEngine.Texture2D icon, System.String resourceFile) UnityEditor.ProjectWindowUtil.CreateFolder ()

When I launched this project for the first time after taking the break from it, I had to reapply the materials to every single one of my game objects that need one.

All of my other 3.5 projects work fine, I'm not sure why this one decided to break all on its own! Anyone have any suggestions or comments? I'd love to be able to save this project as this one was made during a change between version control and it's the only one on my hdd that isn't backed up somewhere (typical..isn't it?)