To me it tells of someone who was either cheated on or left for another by their SO, and they are looking for answers. The depression that they face makes life seem unlivable, and they're looking for someone to save them, as the last line states.
Guilt is a terrible feeling, and it's hard to get rid of even for small things. But if there's anything good to say, at least you do feel guilty for your actions. It shows you have a conscience, and no person with that is truly bad.
It was. Eventually we all have to realize we all make mistakes, and what we need to do to make amends and move on. I'm sure you will do the right thing.