It looks like you could have done lots of things. What exactly were you doing when the problem started?
You need to take it one step at a time and back up good copies. Maybe start over with the file you had this morning that seemed very close but had a gap below.
That way when you make a change you can see the effect. You will know what you did to cause a problem, and you don't have to ask what change you made. It might sound like a slight difference, but the difference may be between being able to help or not. If you do a bunch of things and say "what did I do wrong" without even being specific about what exactly you did and why you were doing it, it is nearly impossible to tell you what you did wrong.