Need advice on my life: cutter, family, abuse, college, house expenses,?

I'm a cutter and can't remember anything. My family thinks it's out of laziness or lack of trying hard enough, but it's not. I have flashbacks all the time (mostly of bad memories) but forget them almost instantaneously. I juggle 35 hours of work a week, college, and house expenses. Nothing satisfies my family and memories of my abused past float in and out of my head. Sometimes I'll be crying or angry and not know why. I cut up my arms to help ease the pain inside. It feels like all the bad stuff inside of me leaves through the vents that I cut. I know it's wrong, but it always brings me back to reality. I'm not suicidal, I just need release. I can't seem to let go of the past, though. The things my grandfather put my siblings and me though--amongst other things--haunt me constantly. He's been dead for years. Even though I'm scared of remembering it all, I feel that I must in order to move on. How can I force out my repressed memories, maintain something similar to sanity, and make my failing memory stronger?