The Washington State laws covering reasonable accomodation for disabled workers is a lot more employee friendly than the federal ADA. This is probably why the attorney from Illinois did not have anything helpful to say.
Based on what you have written here, I believe you DO have a hostile work environment. The devil is always in the details, so I can't really give you a "100% yes" answer, but it sounds like you have several things going on (failure to provide reasonable accomodation, failure to provide breaks as required by statute, retaliation for attempting to enforce your statutory rights...there may be more). Your situation is also complicated by the fact that a union is involved. You might have to exhaust the grievance process through the union before doing anything else.
For these reasons, I would recommend that you discuss your case in detail with an employment law attorney. Many will do an initial consultation at no charge. In Washington State, you have a private right of action in such cases (meaning you can hire an attorney and deal with this without involving the EEOC or the WHRC if you want, so if another out of state attorney tries to tell you that you MUST go to the EEOC first, ignore him or her.) The EEOC and the WHRC will not charge you, but I have not yet encountered an employee who had a positive outcome with these agencies. I'm sure it happens, but I suspect not as often as it should.
Just having a rotten boss is not enough. An act of sexual harassment on the part of your boss or co-workers can be viewed as hostile. An act or any remarks that are clearly discriminatory regarding age, race, gender, religious belief, retaliation, or disability are also considered to create a hostile work environment.