Draw a line on just how much B S you"ll put up with. You don't have to put up with abuse to your heart, it isn't 't healthy. Yes, she's your mom and you don't want to live with regret ,regret is never a good thing to live with neither is a broken heart. Let her know you love her and with that let her know how you feel if this upsets her then it's a feeling she will have to be burdened with.
Take it from someone that doesn't have their mother around anymore. A little BS is easy to put up with against a lifetime of never seeing that person again or having that shoulder to lean on.
Do not completely shut yourself off. You will regret that
Her bs may effect your health. I'd find ways of dealing with your guilt first.
It can be hard. I had a similar relationship with my mother. I moved on with my life and dealt with my issues regarding her. Now, in her old age, I have returned, but I have learnt to visit with her without letting her effect me. She can still be cruel, and say cruel things, but it no longer effects me. I have forgiven her -- she can be no other way in this life and I am OK with that.
I lived fairly close by (25 miles away), but I drastically limited my visits. Luckily, my wife's family were sane and supportive.
There probably are support groups for just what you are going through. Its very common. A support system is a good thing to have. Good luck. I went through it for 22 years before I was able to move out and on with my life.
Hey, I forgive my relatives for all their bs...as they forgive me for mine :-)
Parents may SEEM to be mean, but they can never be mean...