How to get over a 18 years of insecurity? Is it possible to get over it completely?

I am extremely insecure and anxious but I try my best to hide it. I've been told that I'm independent and mature for my age but most of it is facade. Most of my childhood was traumatic for me. I was insecure since the day I was born. My mother was mentally ill and would leave me gone for long periods of time, threaten to leave me at my stepfathers place, or have child services take me If didn't stop misbehaving. I remember hiding in the bathroom with her many times whenever someone would knock at our door. At school I was severely bullied for many things but I had friends/teachers that I easily became attached too so it wasn't complete torture. I was diagnosed with a mild learning disability(you wouldn't know it) and kids/my mother were hard on me because of that. I so was ashamed to ask for help in school because I thought that would add to my "damage" and make people not want me even more. Cause of that I actually never learned how to multiply or divide. Today I am painfully shy, mute sometimes. People think I am autistic or foreign because I am so shy. I am slowly getting better. I am doing well academically wise, have a couple of good friends and I work but I have days where the little things make me wanna break down, how do you build self esteem from scratch without giving up? What has helped you? I just started seeing a counselor but I'm scared that my insecurities are so severe that he'll refer me to a psychologist or something.