I need to stop thinking that it is just a break from us that she wants and that it will work out in the end
That’s it in a nutshell. It will happen naturally, and sooner if you take the good advice given here.
About self-esteem: it’s hard not to take rejection personally and that resentment is the main cause of your hurt. It’s not you, it’s not her; it’s the situation. This too will pass.
The main thing is not to worry about worrying; What has happened cannot unhappen or be undone. There is only the future. A vast, unwritten future of possibilities and adventures if you open yourself to it.