Anika .. you have every right to be upset and angry and plain ole pissed off !
What your mother did to you as a child would be hard for me to forgive .. you dont just walk away from your children and let them fend for themselves at your age then.
You are not a failure .. you are raising your children with love and they will take that love with them there whole life
I commend you for even allowing your mother into your life.
Hopefully she will stay at your sisters so you will at least get a break from it.
stay strong and take care of YOU !
(((Hugs)))
Ps ... Vent all you want and need to