What's a good way to negotiate ghosts of the past with respect to work and networking?

I’m in a transitional period with respect to work and will soon be picking up something new. During this transitional period, I dropped many of my past friends and acquaintances because I changed and began to have less and less in common with them. If I stay in my field or return to the social or networking circles of my past, then I’m likely to encounter them, which for me doesn’t feel comfortable. In other words, I feel as if my domain or potential domain is or will be crowded by people who have seen me at my worst and with whom I have little desire to humor. In my head, I realize this anxiety trip is a little silly, but without working it out, I’m sure it’ll affect my confidence and behavior. (In the past, I moved around so much that I rarely had to deal with this kind of circumstance.) So how do I negotiate this?