Hi, I'd like to help you with your question.
It sounds like you may have some symptoms of PTSD. Post Traumatic Stress Syndrome can occur when someone is exposed to abuse. If you spent your childhood with a mother who was abusive, it would be natural for you to have at least some symptoms of PTSD.
Being emotionally removed from life is a natural defense mechanism you developed to protect yourself, just as you said. You had to do something to survive and since you could not leave, you protected yourself the best you could.
Now you no longer need the defense mechanism but it is hard to shut off. After all, you knew no other way. You did not have the chance to learn to express yourself normally because you were busy coping with an emotionally disturbed adult.
You could also have some depression as well. Depressed people often feel as if they are going through the motions in life. They describe feeling as if they are on automatic or are robot like. The depression can be part of the PTSD or by itself. You most likely have PTSD given your background, but I wanted to bring depression up as a possibility so you could rule it out.
Going to therapy is an excellent way to address your issue. A therapist can do an evaluation and determine what is causing your symptoms. They can also offer you therapy to help you learn to express how you feel and to address any PTSD and/or depression you have. Any Master's level or Ph.D level therapist is a good option. If you want to find a therapist, talk to your doctor about a referral. Or you can search on line at http://therapists.psychologytoday.com/rms/.
You can also use self help to work on your issue. Here are some resources to help you:
The PTSD Workbook: Simple, Effective Techniques for Overcoming Traumatic Stress Symptoms by Mary Beth Williams and Soili Poijula
The Post-Traumatic Stress Disorder Sourcebook: A Guide to Healing, Recovery, and Growth by Glenn R. Schiraldi
You can find these books on Amazon.com or your local library may have them for you.
There are numerous resources available for people with PTSD. With therapy and self help, you should be feeling better soon.
I hope this helps you,