Sounds like you lack trust in others. I know it can take a long time to fully trust someone to let them in. Everyone's different, you maybe just need to take a chance if you really want to talk to someone. I used to see a therapist, took me a year before I said anything to her. I would just go and sit with her for an hour, she would ask me questions and all I would do is make short answers.
When you feel you are ready and you can trust someone, then you will open up.