I am sorry you keep having these bad dreams.
Maybe the dream is telling you something your subconscious is aware of? I don't know anything about symbolism in dreams, but perhaps it could mean that emotionally you are still trapped in your past or childhood, or have unresolved issues with your mother? Maybe it refers to your mother still having influence over you, and that you feel you cannot get away? So whilst you may have escaped physically, some part of you is still trapped?
Perhaps talking about these issues will help you tackle the problem, and then maybe the dreams will stop by themselves?
I saw a documentary on sleep disorders once. In it there was the story of a woman who had been violently raped by a stranger. She kept replaying the attack in her nightmares, and woke-up each day feeling awful.
With a therapist, she was able to change her dreams. Rather than recounting the event as it happened, she learnt to be less passive in her nightmares. So instead of becoming a victim, she dreamt that she yelled for help. Little by little she managed to change the dreams, until she was physically attacking the would-be rapist and getting away unharmed. Once she conquered her dreams in this way, she apparently stopped having them.
I've never tried such a thing myself, but it might be worth a try. Maybe to get it to work you'd have to practice recalling and changing the dreams whilst you're awake - like daydreaming. See if you change the script to make it a more positive dream.