Hi Miguel,
If your girlfriend left you because she wants to put the work into overcoming her depression, it would be best to leave her to it.
If you keep getting in the way, it may make her start detesting you. This will worsen your chances of her ever wanting to date you again.
Give her space.
Start building more of your own life. Work on growing as a person.
In time, you may discover that you have a much better sense of self than you did when your girlfriend broke up with you.
Whether she comes back or not, you are still better off with a more robust sense of self than without.