<human>: I'm a fairly happy, healthy, and driven person with an amazing family and great friends who are all generous, sweet, supportive, etc. I haven't really had any significant trouble throughout my life, relationship-related or otherwise. 

I did move around a lot all over the world growing up, but I've kept in touch with at least one or two good friends from each place (obviously more from my later years) so that I have friends from all periods of my life that I regularly keep in touch with, and we don't just talk about small talky things. I know they've got my back should anything happen.

But I feel like I have this odd, extreme need to be independent. I have trouble depending/relying on people and letting myself become vulnerable. I think I unintentionally shield myself from pain and the fear of being left alone in the world (which is pretty ridiculous). Not necessarily being abandoned, but coming to the realization that I am alone (if that distinction makes sense...).

It's like the initial protectiveness you can get when you're heartbroken after a romantic relationship, but applied to non-romantic people in my life also. 

I'm sure perceptive people can feel my defensiveness, and I want to be able to open up and not be afraid of being hurt (easier said than done, of course). What concrete steps can I take, in behavior and thought?

Can you give me a shortened version of the text?
<bot>: Never really had any human relationships go wrong in the past, but I can feel myself "shielding" myself and being afraid to become vulnerable to even good people in my life. What little things can I do to stop being afraid?