Most Helpful Girl
On the one hand, you shouldn't insult your girlfriend... on the other hand, it sounds like she pushed you over the edge. That's understandable especially if you were at the limit of being stressed out and not having your own space. I've done that before with a boyfriend (there are times where I have stressful things going on, and even though I care about him I momentarily am just plain pissed off and need time by myself to process what's going on).
Also, it's a little extreme to tell her you're going to break up with her - but then again maybe it will snap her out of complaining (if this has been an ongoing issue) and fix her problems.
Bottomline, I'd apologize to her for snapping, explain where you're coming from, and tell her straight up "I was having a shitty day, but I also feel like you should address the issues you're having because nothing is going to improve if you're just complaining all the time. I want our time together to be fun and I support you; let's try to fix what's going on, and move on"1THIS IS NOT RELEVANT ANYMORE
Most Helpful Guy
In my opinion yes, you went to far. You had no right to insult her, let alone threaten her with a break up over something so petty.
"Men who understand women won't argue with them" - Corey Wayne.
You should have said "Listen, I know you've been through a hard day, but I'm really tired and I honestly can't put up will this mess. Maybe you can come talk to me when you've calmed down?". Say it in a playful sort of way, but be assertive... let her know that you won't put up with it.
Insulting her is just going to lead to other arguments, and now that you've threaten her with a break up, she's going to be thinking about a break up herself OR she's going to talk to her friends about it OR she's going to bring it up in a future argument.0THIS IS NOT RELEVANT ANYMORE