"I am going to guess here, but when you were "being mean" to her, did things just pop out of your mouth and then you realize a couple minutes later that what you said was totally the wrong thing to say and that you just messed up?...AGAIN..."

To an extent, this is correct. There were other times when I was just looking for any sort of reaction or acknowledgement I am in the room.

I am very un-capable of having too emotional of a conversation with anyone. So I got mad and frustrated very easily.

I am also afraid the damage is done. I don't think she has any intentions of working it out and is just waiting for a good time to leave.