Depression is hard, and I get your frustration, but if you are seeing supporting your gf as a scorekeeping card of "I pay for her stuff and I do so much for her" then maybe you shouldn't be in a relationship. A relationship is a team and if you are in a bad place and don't work, she will be expected to pull the weight and you wouldn't appreciate her martyring herself about it either.

Instead of scorekeeping, just be honest about the fact that you see yourself not as a team but as separate entities, and want her to pull her own weight in x amount of time. And let her know what that window is, and if she can't meet it, walk away. Just telling her how you're frustrated isn't going to fix the situation. Be proactive and lay out your needs and let her decide what to do with it.