I absolutely do this. I seem to be a master of isolation so I can definitely relate. It sucks, but I can't seem to stop doing it.

Ya sand here and it is confusing to why I do it?

Absolutely! I don't know if it has to do with depression or what. Sometimes it seems so hard (takes so much energy) to do the social thing, and I guess other times I just feel vulnerable so want to be alone. I'm definitely an introvert who enjoys solitude to a great degree. But even I have my limits, and when enjoyable solitude turns to crushing loneliness, it's still hard to reach out. Weird.

Definately
You have described me to a T
I think that I personally do it to prevent myself from being hurt by people and yet I long to be able to talk honestly to people which I know will be difficult and cause myself emotional pain.
Try opening up slowly, to a certain few trusted indivduals, and even if you just let them know you're having a bad day and need distracting you can then talk about anything under the sun

Yep, been there, done that, still do. It's confusing for sure!

I suffer from withdrawals it is a symptom I suffer from so don't often feel lonely. But do the pushing people away from me as tend to prefer my own space. Maybe as ScaredandScarred said just stops from getting hurt. Or just feel I'm just protecting others from myself.

Ya I think I do that too push away to avoid being hurt again. But then don't get loneliness I feel as well

I know for me only the most persistant people have gotten through.Even though I felt total loneliness I did absolutely nothing to communicate with others?Fortunately a few people kept calling and eventually I answered.I think fear of some type of eventual rejection and old memories definitely plays a part.

Being hurt the first time is kind of like: Okay, well, that hurt so lets move on. The second time we are hurt it's like: Okay a wall just went up. And the more we are hurt, the higher that wall gets. It's very hard to break that wall down, even when someone is very trusting and honest. They pay for others mistakes, and we lose out on something important, because of others mistakes.

I find that depression can be contagious and that's why people keep away from me. I in turn, am reluctant to be open with anyone else.

I understand completely!! This is my life, I'm so afraid of any kind of "relationship" with anyone.. I've been hurt so much in my life, whereas I whether be alone!! I cant allow my heart to be hurt ever again.. So I keep/push people away on purpose!!! So invisible, just know you're not alone!! ((((HUGS))))

always~~~just don't like myself and feel like, why would anyone value being with me?