My 'Invisible Suit of Armour."

Has anyone else experienced this?
My 20 y/o daughter has been estranged from me for about a yr and half. She now lives with her grandmother and aunts. On the rare times they do contact me, it is either mind games, lying or both.
My best friend called me last night and asked me whats up, and about my daughter, which is not unusual. I found myself giving her short answers and asking her about things in her life. (I wanted to spare her the same ol same ol). This time she wouldnt let it go and I found myself spilling my guts about it for the next half hour while she patiently listened. Somehow she sensed that I was having a rough time (a few days earlier my neighbor was telling me about her daughter moving out of the house, how she will miss her, etc... normal things that we have all been deprived of).
My ah ha moment came later, when I realized not only do I wear my invisible suit of armour with her, but for everyone. It is like I am subconciously putting up an invisible wall with everyone so I wont be hurt any further. I dont want to be that way, and until she called, hadn't realized I was doing that. Can anyone relate?