Where is everyone getting abused and gaslighted from. I read this as a guilt trip at worst. Not being assertive isn't some sort of disability (I am assuming OP doesn't have a relevant disability since they did not mention one.)

In any case, blame her 100% for everything that came before, I still think OP is TA for not telling her once they decided to leave. Again, mainly thinking of the baby. And I hope OP gets the help they need or has learnt something from this, because they could be 100% NTA and they would still be at an incredibly high risk of the same thing happening again. I know it sounds like victim blame, but I'm a loss of how to avoid this in the future when their roommate did the bare minimum of a guilt trip and got 6 months rent + chores out of it.