Ideally, your counselor (or behaviorally sensitive attorney) can be an advocate/mediator communicating with the office as to your needs and the office's needs, so that the people at the office can gain a new perspective that replaces their old perspective of you (as someone to use without concern for your well-being). And the office can work with you in an improved way to assure your successful return.
The major problem, and you don't really have to be reminded I'm sure (so this is validating you) the office has gotten used to taking you (and probably others) for granted. And having them shift their perceptions of you, very likely, will be difficult. It is also true that society in general is in denial about the extent that clerical and other working people deserve to be treated fairly---there is a wide assumption that it's OK to overlook people's basic need for humane treatment.
This brings up the very important topic of justice, and injustice. It is likely that you feel your situation is unjust and unfair, and that you are trapped in an unfair situation. This is almost universally true for people we have worked with and work with now in counseling. So it is about learning the truth about "justice" in regard to work. Basically, there is no justice in the "work world"---most attorneys will tell you this as well as counselors, like ourselves, who help working people every day.
To keep expecting justice or hoping for it, is a major roadblock in handling abusive work. Expecting justice and wishing for it is like wanting a parent to be nice (when most parents don't know how to be nice, because they were mistreated as kids too). People who are at the top of most organizations are people who we wish could be just and fair, but unfortunately are not---simply because they are people who often need to see themselves as superior to others (that is, they have not progressed personally, behaviorally to the extent that they can see how they need to empower working people rather than mistreat them).
95 % of organizations are authoritarian, meaning: they do not share power with employees. This is a scientific fact measured at thousands of workplaces by the University of Michigan Institute for Social Research. Injustice is part of authoritarian work structures. Expecting justice is a thinking error. Healing from past injustices and preventing (as much as possible) new injustices is the way to go.
Most working people have not learned this basic truth about work, because it is withheld in school and by society generally: that each working person when employed by someone else will be working in an authoritarian environment (being given orders without consultation)---and that means each person must learn how to minimize being mistreated----without blaming oneself (maintaining self-respect) for having to "cow-tow" in order to survive a basically unjust situation. This is a tough, tough learning.
In order to return to your office employment, or to take any job where you are employed in the future means you have to make a shift inside yourself away from dependence on the employer for "fairness." This will require acquiring behavioral skills (after healing from you present emotional injury) so you can take a job, and do the job in a more empowered way---that would include setting limits in a way that you can truly be heard. This would likely be a very big behavioral shift for you.
Skillfully setting limits so that you are not overworked at the office where you have been employed and already used, probably sounds totally impossible....and feels totally impossible....so you have to embark on behavior change on faith...this is very hard...and a big shift. And it is basically unfair. That fact of unfairness can not be changed in the foreseeable future---this country is built on working people being treated unequally: this is a fact that is much too easily denied as a national myth (the myth of "making it" includes using/mistreating other people in order to "make it.")
To sum up this message, it is important to work with your counselor to develop behavioral skills you will need to survive in an unfair work world (this includes understanding how others--possibly even your friends and family--still are stuck in expecting fairness, or insisting the office is right and you are wrong---which is the mistake of seeing authorities as "correct" and you as the working person as "wrong"). Finding other people who have made the realizations you are making in order to validate you and help you keep your self-respect would be very important right now. We have no answers on this. There is not even a forum for such sharing on the internet (as there is for other types of abuse).
There are not many people, yet, in this position of developing true awareness about work and the abuses that are too common. It is only lately that people are coming out of the dark ages and becoming conscious of the truth about work. This is not to blame managers. Blame is useless. The problem is ignorance by managers (who have the responsibility for work systems) and by working people (who project too much power toward the managers).
Abusive work will end when workers wake up to their abusive situations, build the behavioral skills required to survive in these unfair situation---- and collectively begin to demand democratic work. This is not going to happen tomorrow; but building your skills can begin now, and that is the only really hopeful way out of your situation.
We hope this helps...We would be happy to communicate further, including with your counselor.