Although... if part of the issue with your old job was that they expected a tonne of overtime from you and that hadn't been part of the deal initially, I would mention it. It's good to be very clear on the expectations on both side.
I'm such a xillenial.
Too young to be true Gen-X, but too old to be full-on millenial. Behold my entire lack of understanding of new technologies.
And I have a ridiculous attachment to stability. Mind you, that could also be a byproduct of the entire lack of it in my childhood...
Anyway, I'm totally with you on not sticking with the old job if it was making you miserable. I don't know if your mother is a boomer, like my parents are, but they do tend to be controlling and to not understand that their children have become adults who can make decisions on their own and be responsible for said decisions, whatever the outcome is.
The thing, too, is that being impulsive isn't inherently wrong. I mean, we all have to be true to our true/deeper self, or whatever, right? The part of us that makes up our personal values and seeks existential satisfaction. And if your deeper self knew after 3 months that you didn't belong there...
I do want to add that I think it's a good idea to test that feeling before acting on it, because sometimes there can be course-correction. Or, in my case, I have issues with things that are new. It always takes me a while to adapt to just the newness of something. But, beyond that... Just because something seems impulsive doesn't mean it's wrong.