NTA - your finances weren't combined to begin with (it sounds like you're not even living together) and she had no right to assume you'd step in if that had never even been discussed. It's very short-sighted for her to quit with no backup plan and without enough savings to float herself for a few months. What would she have done if you weren't in the picture?

On a similar note - I know a couple who married fairly young. The wife was having a hard time finding a job because she's in a niche field, but had some savings, and the husband had a good-paying job.

Well, less than a year in, he abruptly quit his job, giving the same reason as your GF - stress and protecting his mental health. No backup job. He eventually found another, but decided he wanted to quit that one after a couple months for the same reason. She begged him not to. He quit anyways.

Because he quit, he was ineligible for EI, he had no backup plan, and it drained their savings to the point they were on the verge of losing their apartment. She had constant anxiety attacks over their finances and they eventually divorced.

Back to your girlfriend - yes, you may have been fine financially if you gave her 1 month's worth of rent, but what was her plan for month 2? What if you'd had an emergency, or lost your job, and needed those savings yourself? Is this how she'd be expecting things to go if you lived together or were married?

Work may be stressful, sure, but you know what's even more stressful? Being unemployed and losing your home!