I have a coping mechanism called dissociation whereby I fragment my mind into multiple pieces to prevent myself from feeling my own emotions. I invented this in childhood as a result of severe trauma both in and outside of the family. It works really well. Too well. Because now all I am aware of is a very tiny slice of life and subconscious defense mechanisms are constantly pushing anything I might not like out into the ether. I am trapped inside my own fortress of defenses. Holding up the walls to the fragments takes a lot of energy, and so I am very tired. Also, since most of the emotions are pushed away, I feel like a robot a lot of the time. How do I bring the walls down and fire the wall builders and let the emotions flow? I have felt it occasionally and it feels like the central channel becomes available and like my "self" is a constantly changing flow rather than a rigid numbness. Please help me get my emotions flowing. I want to cry like a baby. I can't cry with these defenses protecting me. It sucks not to be able to cry.

I would suggest mainstream psychology would be a good angle for recovery and understand it will probably take a few years.  Heavy trauma can be way too much to deal with all at once.  You will need to assimilate it bit by bit.  A mountain is tackled boulder by boulder.  I would suggest something like cognitive behavioral psych or similar (not Fruedian)  ALso, the guy Ron at alohadharma.com is a psychologist, he might be worth a checkout (anyone know much about him?  Looks like he studied dharma under Kenneth Folk).  Meditation can also help with such problems but was not really designed exactly for heavy trauma and most dharma teachers are not qualified to deal with such either.  The best results seem to be had with a synergy of both high quality mainstream and spiritual work.  Meditation can show you the peace and healing of a quiet mind but the mind will also need to know how to operate cohesively and peacefully when needed as well.  Unfortunately your mind developed in difficult situations where survival and avoidance was the main and only reasonable goal.  Now when it comes time to want to thrive in a very different environment, your mind will need to change a lot of things it learned in the past and that takes some time  Your mental habits were probably well suited to their initial environment but now the environment is probably quite different.  Seems like almost everyone faces the world's challenges with the skills they learned as a child, but if those skills do not fit the later environment, that person faces additional challenges.   

I strongly agree with Eva that psychotherapy is the way to go. However, as long as the effects of meditation are not overwhelming I would stick with it, too. Due to traumatic experience I have shut off intense emotions, too. Both, therapy and meditation, so far have helped me a lot to reconnect with them. Good luck and all the best for you!

+1 for integrating psychotherapy and meditation in your case. There are even approaches that do this explicitly, e.g.

https://en.wikipedia.org/wiki/Mindfulness-based_cognitive_therapy

I agree with the therapy suggestion, but I would suggest avoiding cognitive-behavior therapy (CBT). CBT focuses on challenging "dysfunctional" thinking through more cognizing, and can have a very combative feel to it. But some other therapies are reported to be particularly good for trauma, I think EMDR (eye movement desensitization and reprocessing) and Coherence Therapy.

See http://shrinkrapradio.com/330-unlocking-the-emotional-brain-with-bruce-ecker-m-a/ (it's an interview, you can read the transcript or listen. Someone else posted to DhO some time ago.)