Change works best for me when I feel I am going toward something rather than away from something, especially if I am rooted in anger and fear. So maybe this is all about perspective - you've sized this situation up and it isn't healthy for you and you are leaving to seek something that feels healthier and feeds your spirit.

Giving a notice and serving it out is important. Years ago I left a job without giving a notice and I felt like a failure afterward.

Best wishes - I hope this works to your advantage.