Lonely

All my life growing up, I was told not to show emotion not to get attached and not to let people in. Now I am in my 20s living on my own and feel so alone, I can’t have good relationships because I shut people out, and have a fear of getting attached. I’ve been a caregiver my whole life to my parents And I seek to fix people and every friendship/relationship. I don’t know how to stop this and I wish I could open up to people, but I don’t know how anymore.