This used to happen to me as well. Every new place I started, at the beginning it was fine, but after while I started to feel uncomfortable with some of the people and feel like not belonging to the group anymore.

What fixed it for me:

- Changing jobs also getting a higher salary / more to say over other people.

- Challenging myself to just do the things I fear. Just walk through that section, just do it, overcome it. No need to talk. Just walk there, look out of the window if there is one there with your coffee in your hand. Relax.

- Not putting too much energy into talking to people if not needed. Better to talk less than too much.

- Socializing more outside of my job to become more certain of myself. No need to go to disco clubs or bars, even going to hackatons and meeting new people will help.

- Learn to represent myself better and being aware of my looks (ask friends or family to help).

- Not taking things too personally.

Have you considered trying to do just remote work for a while ? It may, at the very least, give you some time to relax and not be subjected to the crap that you've been dealing with. I think you'll find that dealing with customers, while still problematic at times, can be much, much easier than dealing with coworkers that are jerks. You can always fire the customers. :-)

You're not alone, so take that unknown off your plate.

If you want to talk privately, email me.