Suffered from lots of abuse in the past... How to get over and move on?

My mom has severely abused me , physically and emotionally. I am now in my twenties and I am pitiful. If she is displeased with me or even comes near me , I instanty squeeze my eyes shut or cower.. expecting some cruel treatment. It has become some kind of reflex and its embarrassing when it happens infront of others. How do I stop this? Please Help!
Suffered from lots of abuse in the past... How to get over and move on?
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