About zoloft, abilify and vistiral?

I had recently been hospitalized and the psychiatrist there wanted to put me on a combination of zoloft and abilify and vistiral only to be taken when I needed it. I am wondering what exactly they do and what they are used for. No one every really told me what exactly was wrong with me but now I am seeing someone who believes its BPD. I have a type of friend (not a real person, like a split identity) that I talk to, usually there for me when I need her to reure me she would never leave me. However, sometimes she can be evil and beats me/makes me cut myself. I get in deep dissociative states when emotions get very very intense and that is when most of the harming occurs. My base mood is usually apathetic/melancholy. What exactly could these medications do for me? I'm very skeptical and afraid to take medication.