Hello, first post here
I'm currently having an experience that is very relevant to this topic. It's my freshman year of college, and I'm living in a dorm, sharing a room with another girl. Now, before I left for school, I told myself "Oh, don't be so negative. Maybe it won't be so bad." Many times, I think like that, but I know myself, very well. My original feelings prove to be true quite often. It would have been unpleasant sharing a room even if I had a great roommate, but no. I have a terrible roommate. I won't list all the reasons why she's terrible. All I know is, this experience will never be repeated if I have any choice.
The way I feel in the dorm is akin to suffocation. I swear I can't...breathe. You guys must know what I'm talking about. The mere presence of another person can be a very disruptive thing, for me at least. When I think about myself in terms of my extreme introversion, I know that there needs to be a certain ratio of public to private life in order to retain my sanity. Here's the thing: I consider public to be any realm in which I share a presence with a person with whom I am not close or comfortable (i.e. a stranger). Under this definition, 100% of my life is in the public realm, besides my trips home (seldom). I cannot convey how much this bothers me. Suffocation. I can't think straight. Heck, sometimes I can't think at all. I can't hum to myself without her asking me to to stop. I can't sing my music. I can't dance crazily. I can't even be naked or go to sleep in the buff if I choose. It is driving me insane. I want my peace back, my solitude. I need to be alone so badly that I want to scream. When she leaves for any length of time, I can't describe the feeling that comes over me. Honestly being so unhappy with my living situation is sucking a lot of energy out of me. I don't feel that I'm exaggerating when I say that this is really taking a toll on me.
Also, I believe that it's having a negative effect on my social life. When I get all the solitude I need, I'm perfectly okay with being around other people a certain amount of time in the day. When I get all the solitude I need, it's easier for me to make acquaintances and friends. However, when I'm starved of my alone time, I tend to hide away in order to get any alone time that I can, so I spend as little time as possible in public, so there's less of a chance to see people and get to know them.
Living with family is a different story. I'll always be introverted, but at home, I can have all the alone time I crave while still having social interactions with people I love. I love living with people I love and care about, people in whom I am emotionally invested. Sharing an intimate space with a complete stranger (an incredibly rude one who has no interest in getting to know me, at that) has made me realize what I have at home.
ETA: Oh, and I've never lived completely alone before. It's likely that at some point in my life, I will. I don't think I'll relish it though. Sure, I need a good amount of solitude, but I also find a lot of joy in living with people (or a person) I love. So, living alone wouldn't be ideal for me.