How to overcome fear of looking stupid or feeling insecure about things?

I know exactly how you feel. For me, it ended up being a generalized anxiety disorder. It took years for me to confront this and seek help. I am well these days and much happier. Go see someone--and not a psychologist. Be honest with them. In my experience, "talking" to someone doesn't help in the long term. A correction of chemical imbalances solves the problem. Good luck.