Writing about the past

I am finally giving in and writing about my past so I can understand what happened then that is making me the way I am now.  It is tough.  To remember everything done to me is painful.  My childhood reads like being trapped in a cult minus the religion part.  I don't want to go into details here- it's enough just to get it down for my therapist to go over.  I feel drained, tense, and heartbroken after writing just one page.  That one page is just the beginning.  I feel compelled to get it out, to stop it from haunting me, but it is like pulling out glass from your skin, one sliver at a time.  How may times is this going to make me bleed until it heals?