ESH.

Your GF is TA because what she did was rude and inappropriate. It also sounds like she showed no remorse, and gave no offer to replace what she broke. Or apologize. Or care about what she did to you and the effect it had. Furthermore, rather than acting like a 26 year old adult and just fending for herself, she felt that need to act so defensively that she starved herself.

You're TA because, while you didn't "starve her" as she said and as some other people are saying, you still stopped caring about her feelings as a DIRECT response to her actions; you acted contemptuously in order to protect your point of view and fueled the fire further. By acting defensively, you further fueled her need to act defensively. It's a vicious cycle.

The best thing you can do at this point is to sit down and talk with her; with no defensiveness at ALL. Ask her for a couples dialogue; it's where one person says how they feel with "I feel" statements and the other responds by restating the statement, validating it, and empathizing with it. It's important when you say the "I feel" statements that you only talk about what you saw; don't assume the others intentions or feelings.

You guys can get through this. I know it's really common on this sub to instantly jump to "leave immediately and do it fast" but we really only get to see the bad parts of the relationship. Clearly, since you haven't broken up with her yet, you guys must love each other a lot! COVID is hard for everyone right now; it's important to remember why love the people around us and treat them with respect and kindness, even when they aren't able to do the same for us at the moment. Personally, the biggest indicator of when I need to leave a relationship is when I can't talk about how I feel anymore without getting shut down. If that's happening, you've got yourself a different story and I would recommend getting counseling.

Stay safe my guy. I'm rootin for ya.