Harrment and Stress in the workplace? What are my options?

I've been working for a very large government contractor on a military installation for almost four years now. I work in an office environment with many conflicting personalities. The problem with this is that when problems arise, there really is nowhere to go. Nepotism runs very deep in this company. I would say that about 20% of the 300 employees are related in some way. And most importantly, almost all of the upper dozen management are related! Although we are all in the Teamster's Union, the union will not give it there all because I've been told, "Don't rock the boat" as well as, "You know how things work around here, with this family". So, there's my problem. I work in a very hostile environment and I think my number is coming up. I get written up for any little BS thing. They go through my paperwork and files looking for dirt anytime I may call in sick or take a personal day. The last time I was being written up, I did not sign the paperwork because the union guy sitting in with us called BS, and finally spoke up and said, this is obviously a witchhunt. The boss threw out the paperwork and told me to leave. I got out of this last one, but now she is smokin' mad! And I know she's out for revenge. Anyway, I am really stressed out when I go to work, I work in a hostile environment where I am always looking over my shoulder. I have nowhere to run to because all of the management are brothers, sisters, spouses, cousins, it's ridiculous! I am going leave this job because I can't work in these conditions, but at the same time I feel like they got the best of me and that "they" won by running out yet another good employee!!