Have you read about attachment theories in regards to adult relationships? I am like you, they call it anxious avoidant attachment style. I want a relationship, but I'm afraid of it too. so I avoid, or I find people who are also avoiders. (emotionally unavailable I suppose)
it's not a fun state to be in that's for sure. but try not to give up, and if you aren't in therapy, perhaps that would be a start?
there's lots of reasons why we have this type of attachment style, most of it rooted in our childhoods. I feel certain there is someone out there with a stable attachment style who will connect with us and give us what we crave but are afraid of at the same time.
I wish you the best.