I read about your situation and said “wow” out loud. You seem to be in quite a difficult predicament. So, try to step back emotionally and take a look at the situation from three perspectives. You may have more control than you imagine.
You can change
You work in a toxic environment, and the boss is horrible. Despite that, is there anything you can control in this situation? If you’re going to keep the job and your sanity something has to change. I assume your boss is not going to be that something. So, that leaves you.
Change your response and reaction to situations. You may have said to yourself at one time or another what action you should take to gain control. Think through that again and do it.
Distance yourself emotionally. Can you ignore some of the craziness, or disengage from the conversation? Can you limit talking about it as much with others (if that is the case)? In other words, how can you focus on different aspects of work (or life) that isn’t toxic?
Distance yourself physically. Can you get out of the office more often? Leave for lunch, visit clients or run work errands? Can you work from home, even one or two days a week? You know your situation, so ponder these questions. The point is to change your reaction (physical and mental) to your boss’s antics and gain a sense of control.
You can get support and counseling
I assume approaching your boss is not a viable option. But, I do suggest that you talk to a trusted advisor and identify some other ways you might cope.
Get involved in a professional group, interact with healthy people, and hear about other job opportunities at the same time.
Get involved in social outlets or community activities to remind you that there is a life outside work.
Seek medical advice. You are depressed, anxious and not sleeping. Do not overlook these symptoms. Does your company have an Employee Assistance Program? EAPs can be a great company benefit, but most people don't access it. If you go to church, explore options there. You need an outlet and someone who can support you during this time.
You can leave
I won’t question your reasoning to stay. I understand the pull to hang on to a stable, well paying job especially when you have obligations and support others financially. Been there, done that. And, I’m guessing since you have a 30-year career you are hesitant to leave for the fear you won't find comparable compensation. Regardless,
Update your resume, and start networking. You always need a resume, so update yours.
Get a free resume review at Resume Robin to improve your chances of being noticed out in there in the big world.
Get out more. Going to networking events, and talking with others can help you feel less isolated and trapped.
Get involved in LinkedIn groups to find similar professionals and stay engaged.
I hope this is helpful and sparks some ideas on your part. Let me know what you decide. Hang in there and take care of yourself.
Your Office Mom