Wubba, there is good news and bad news for you! One day you will be able to handle your relationship with your mother. The bad news is that your cannot change HER. You can only change yourself, and that means maturing into a fully responsible adult.
I have had the same experience with my mother. It has taken years for me to understand her. She still causes me a lot of pain, but I know that the bad stuff she says and does is part of her condition: she has a personality disorder. I have learned that the only way forward is to forgive her, but at the same time be realistic about her problems. No mother is perfect, some of them are worse that others. You and I got stuck with a couple of bad ones.
You need help from another adult who understands what is going on - your boyfriend/ husband is the best person to help. You need someone to talk to who will support you and help you laugh about it, and get things in perspective.
Don't let her games upset you. She is trying to manipulate you. Act like a responsible adult and you will be one, even though she isn't.
Try to believe in yourself. You know, Christians have defensive weapons that can really help. When she attacks you, hold up your shield of faith (believe in yourself), so that she can't stick knives in you. Don't let her get you involved in arguments or manipulate you. Say what you mean, say "I love you, mother, but I can't cope with you right now," and get out of that fight.
Have someone with you when you talk to her (no private phone calls), so that you can talk over what happened, and decide how you could have handled it better.
Above all, don't hold any grudges against her- that will make YOU unhappy. Forgive her, and try to separate her bad behaviour from the mother you really love. As Christians say, hate the sin, but love the sinner.
Behave like an adult; don't get caught up in her twisted thinking, AND take lots of time out from her.
While she is grieving for your father, she may be behaving even worse than usual. She is a widow, and you are an orphan. You can't take her whole world on your shoulders, make sure you share the burden with others (brothers, sisters, friends). Allow yourself to grieve for your father, that's very important.
I hope this helps you.