No, you are not “insane.” During the abuse, your conscious mind was “tuned out.” Your unconscious mind took over in order to protect you. Dissociating during a traumatic experience is not uncommon. Dissociation is a psychological defense mechanism.
One reason to explain your inability to recall the “meat” of the abuse is that you are not psychologically ready to handle those memories. Your unconscious mind may be protecting you from having to relive potentially painful and traumatic memories.
You may never have total recall of the abuse. You cannot force yourself to remember. Defense mechanisms are not within our control; they are unconsciously generated. Perhaps those memories will be revealed to you when you are psychologically ready. Only time will tell.
I would encourage you to read about psychological defense mechanisms, dissociation and abuse. It may help you to better understand your situation. You may also want to consider seeing a trauma specialist. Please take care.