Welcome to NMP
I think anyone who has suffered form an anxiety disorder will understand this to some extent because we all start to wonder if others can see how much we are panicking inside.
It sounds like this is very much a behavioural issue that was conditioned by how you were treated earlier on in life. You've started to shield yourself from the potential harm that othe people could cause you and you have issues with trust. No doubt how you were treated really affected your self confidence, self worth & self esteem.
Its going to be useful to explore how to build your confidence and to consider how you view yourself in terms of self worth as these greatly impact self esteem.
I think you also need to retrain your brain to prevent going into these saftey behaviours so that you can feel more comfortable around people.
Have you ever tried Mindfulness? This could help you because it includes acceptance and compassion. (to yourself and others) This might help you feel more open as its proven to stimulate the compassionate side of the subconscious which makes us happier. This might help you feel more comfortable around others and at the same time prevent your subconscious kicking off the safety behaviours.