((Hugs)) I too had an evil step mom and now have PTSD from it. And yes I've had many nightmares about her. You may want to get checked out for PTSD?

What did help was closure. I hadn't seen her in probably 13 years and my half sister took me over to her house because she had to get something. Well "evil step mom" (actually ex step mom) took me outside and started crying and apologizing. She rambled on for a good ten min. As much as I wanted to spit in her face, it did bring me closure. The nightmares have stopped. I just needed to know that she was aware and felt bad for my upbringing.