I have a strong feeling it's this.
Well, there is nothing wrong with a healthy fear of such, but not to the point where you get anxious about it. I know how you feel, though, I feel very similarly. Try staying along for increasing periods of time, each day adding another minute or so in complete isolation if you fear this is at a phobia stage. :o
However, maybe something in your life has just come up, and you want to remain close to those around you. Maybe your having a difficult time reconciling with your childhood as you are now getting older. Could be a number of things, really. Recognizing it is important, though.
