Hi cthonica, and welcome to the forums!
I have Bipolar II disorder and Anxiety, and like you, have found that dealing with customers, vendors, even co-workers can be a quite interesting ride. I do try to network, but only because right now I'm working as a contractor with no benefits at all, and I need a full-time job to get those. Networking make me uncomfortable. I'm sure that everyone I meet is taking an inventory of all my shortcomings. I've been very selective about the people in the business world that I've disclosed my disorders to, I have to feel I can trust them. I haven't been let down...yet. I also have my own business and none of my customers know about me, and they never will. I think I've told certain people that I work for because I don't want it to come back on me that I withheld information from an employer.
When you say that you do the auction thing, is it a face-to-face auction, or one that's online? How much direct contact do you have with your customers? Does it cause a lot of anxiety? If so, are you doing anything to deal with that? Meds are an option, meditation can help if you have good concentration techniques, breathing exercises are good too. You've also described some things that sound like ruminating thoughts to me. Those being thoughts that start with one thing and build to another, and another until they get out of control. Am I right about that? There are some meds to help with that, like Zyprexa, Geodon, Abilify. I'm sure there's others but that's what comes to mind.
This all being said, I am not a doctor, and you should take anything I say with rather large grains of salt

. I'm just throwing out some ideas that you might talk to a doctor about.
I wish you all the best of luck, and I hope you'll let us know how this turns out. Again, welcome to the forums!
Greg