I wouldn't say it's a constant thing in my life. It goes along with rough patches when I feel like maybe I'm doing something wrong, or I AM wrong/flawed/unattractive/broken etc...and that's why certain things (some friendships/relationships/job interviews/whatever!) don't work out well in my life. I fret about how I come across, how others see me, and whether I should be doing something to change that.
Periods of low self-esteem, I guess. But I wish I had the cast iron self-regard that some people have. Well, not that I want to be conceited. But I'd like to be more secure in who I am and not take my self-esteem from how others see me or react to me. Again, not that I'm doing this all the time...but I feel like it happens too often.
Is this a problem for you? All the time, some of the time? What does it coincide with? How do you deal with it when it comes up?