Hello and welcome to HealingWell,
I am wondering if you do not have grounds for harrassment in your work environmental ? If you have proof your co-workers are causing your stress and anxiety I would talk with your boss as this is not right.
I can understand why your confidence has taking a hit !
Self confidence usually is based on how well or not so well we've done in previous situations. It is how we feel about ourselves. Our self worth is based upon our previous performance . We all tend to base our own personal values on how successfully we perform in different situations and we often want a perfect performance of ourselves. If we don't live up to our perfect standards, we end up lowering our opinions of ourselves.
We can learn to value ourselves in spite of feeling anxious. . . As adults we often believe we must continually justify our place in the world, that we have to somehow prove to other people that we are , extremely self confident and worthy of their esteem . We will spend excessive amounts of time feeling anxious and afraid that we won’t meet other people expectation and we lose sight of the basic fact that we are usually all right just as we are, in spite of the fact that we are not perfect. Don't underestimate yourself and remember if this co-workers are nasty there are many good people out there.
Believe in yourself.
Kitt