J.
Hi Amy!
Sounds like this girl is threatened by you. I have found that when someone behaves the way your coworker is behaving, they know they are not doing what they could do to be the best at their job. In order to make herself feel better, it seems like she is picking on you because you are doing 110%.
Sounds like it was no mistake on her part that you "overheard" her complaining about you. I have learned that people that think like this do things in a very intential way. Please rest assured that you are being the best person you can be, and because of whatever reason she has, she must make herself feel better by knocking you down.
It is really silly to criticize someone for chewing loudly! Come on, we all eat! If you look at it from a different perspective, removing yourself from the hurt she put on you, it is quite funny to expect someone to make no sound when chewing! And as for having to listen to your personal problems, it is her choice to evesdrop or not! I would go about your day changing nothing! Maybe bring in some gum and pop it to annoy her more! Nothing like being passive aggressive!
You really do sound like a great person, and awesome worker that has challenged a slacker! Be proud of who you are and what you stand for and don't let her petty cattyness change that!!
Good luck!
J.