Returned to work after maternity leave and now quitting

I returned to work after maternity leave but I got a new manager because my old one quit. I loved my old manager and this new one and me just aren’t seeing eye to eye. My 40 hour work week is looking more like 50 hours now due to all of their new deadlines and demands. My HR manager allowed me to have an earlier schedule after my maternity leave so I thought I was in the clear. But clearly I can tell that this new boss has a huge issue with my modified schedule. She has made multiple jabs at me leaving at 3pm which in turn made me work more to prove to her that I can. It’s affecting my mental health and I don’t feel like she respects my parental duties outside of work. The worst part is that I am spending less and less time with my little one (who is currently 6 months). I’m putting in my resignation today because I can’t take it anymore. I’ve only been back to work for a month. Did anyone else go through the same thing after returning to work?