Uff. I feel you, as I have depression as well and have treated people poorly as a result (which I only realised later, once I was better - thanks, brain).

I’m a bit confused on the timeline here: Her comment that you needed a breakup to act nice and attentive kind of implies that she feels even after you returned to your field and got out of your depression, you were still not being what she needed? Is that right? Because if she isn’t satisfied with ‘non-depressed you’, it is a different situation than if she just hates the depressed period.

What has definitely happened, is that your depressive episode left it’s mark on your girlfriend - and you need to talk about that. She needs a chance to verbalise her hurt, confusion and what she went through, while you were trapped in the depression bubble. Hate is a strong word - there is a lot of emotion there, which she hasn’t really worked through properly. I feel it might also be worth while looking at what happened on your end - how did you slip into asshole mode and how far? Did people point out that you were an asshole and you refused to get help? Really open up about how you felt during that time, including all vulnerabilities, though be very careful that you don’t slip into comparisons or a pity party. This is about her emotions and so she can understand what was happening at the other end, to help her contextualise what happened.

What I’d also do, is make a proactive plan. You’ve now had a depressive episode - you need to learn from that. “Don’t work 70 hours per week in a dead end job” is not a sufficient take away. What were the early warning signs that your mental health was slipping? What are symptoms you can look out for? What were the steps along the way until you reached rock bottom? What are you going to do at each of these stages to break this pattern before you turn suicidal, if this happens again? Showing that you are doing your damnest to prevent this from ever happening again, will do more than any assurances that it is over (also, incidentally, will be worth a lot, if you start slipping again - with or without your girlfriend. My tip is to stick that emergency plan somewhere where you can easily access it AND give a copy to your best friend, as sometimes others can see what we can’t).

After all that, see if she is prepared to allow for healing to happen. She might still want to break up, which sucks. Whatever happens, she will likely need time to digest. This will also not be done in one evening’s discussion and will likely keep bubbling up for a while. Honestly, let her dictate the pace. Feel the mood. Allow her to shout at you and cry if that’s what’s needed.

I wish you the very best. It sucks when depression massacres a relationship, but sadly it happens. At that stage all you can do is try to repair and attempt to learn for the future.