Feeling hopeless, sad, disappointed?

I've been really low on life lately and really struggling to keep myself strong, positive and confident. I feel like my past is catching up to me. I had some troubled family times a few years ago (emotional and physical abuse) which resulted in me losing control and destructive behaviour that has now affected me and left me with reminders. Although i thought i had overcome the problems i had they are always there holding on to me and pulling me along on a rollercoaster ride, back and forth shaking me up. I was happy for a while but all of a sudden the last couple of month ive just dropped down so low and cant find a way to bring myself up. My school work is struggling and relationship with bf and friends isnt too good. I'm worried that all the memories and scars from my past are going to always be there to haunt me and remind me of those times.. All i want is to be free, okay and happy with no strings attached. Any one with good advice on overcoming this or dealling with the situation at present would be appreciated :)