Well, not much to go on, but what you've written seems to answer the "why" you feel low.

You feel detached from people you love for "a long time" and that makes you angry, and makes you sad. What can change? Ask yourself honestly what has happened and what stops YOU from contacting your parents or any loved ones? Reach out, if not to them, then to a trusted friend, or better yet a counselor. There are folks who want to help but it's up to you to give yourself that help! Your message here is a good first start, and I hope you take the next step. You do not have to stay so unhappy.