I've found feelings of disappointment, anger and sadness about my childhood well up whenever I'm pregnant. I found seeing a good psychologist really useful, but they still flared up when I was pregnant again.
I think a mix of pregnancy hormones, feeling more vulnerable myself whilst heavily pregnant, planning for parenthood and having more free time to ruminate on mat leave.
I can't understand how my parents were so unconcerned about my emotional health and wellbeing, I really can't. I spoke to them, which helped me feel better to have said it out loud, but I don't think they can understand it. They just don't have an understanding about psychological/ emotional stuff, they seem to have either not developed it or repressed it!
But after baby was born I did reflect that parenting is hard, especially when you had a bad childhood yourself (as at least one of my parents did). I won't forgive them for not trying harder to break that cycle, but I can understand a bit why parenting wasn't easy for them.
If you haven't already, I found seeing a good psychologist really helpful to talk all this through.
Do take some distance from your mum if seeing her upsets you. I didn't want my Kids to see me tense and upset. When they were older I chose to re-initiate contact, it worked better by then.