I'll tell you something that you don't want to hear but you will remember it one day..

Listen when people talk and when somebody tell you who they are, believe them!

She seem manipulative to me. She pretended and you didn't know her until she moved in. Her crying to her parents and saying she is a failure and she spent all the "money" .. Was it just a show for money and nothing to do with failure? She seems like a lazy person who have excuses.

Is she sharing a rent with you? For her money is very important and not to waste her parents money. You definitely could do better and find someone who will love you for who you are! She is not loving you and it's hard for you to process that. Maybe you should go to therapy and understand when someone tell you "you could do better" ..what that means and what other person is telling you unconsciously.. I'm sure you don't feel "loved", not coz of her mental issues but because you are not loved ... Maybe I'm completely off but it's not over yet and you could be in denial...