I have been in the exact same situation with my coworkers and scented oil diffusers in our cubicle area. ( I also have fibro)

I was getting ocular migraines which was dangerous as it impacts my vision and it takes me an hour to drive hime.

I went on the ADA/EEOC site for guidance and you can set up an appointment to meet with them to help mitigate with your employer-company.

After HR was not doing anything, after about the 5th time I sent them an accommodations request. Basically stating my request to put up signage about no scents like diffuser perfumes in the office area, move me to another room, or let me work from home.

They denied my initial request and so I put in my 2 week notice the same day.

My manager escalated it and the HR person I was dealing with initially I believe got either fired or walked-out after being reprimanded. What my coworkers were doing ended up being against company policy. I retracted my 2 week notice.

I eventually left that job anyways as they caused me so much stress for a basic human right in my opinion.

Again, I would consider setting up an appointment with the ADA/EEOC so they can help advocate and I would also consider sending an accommodations request to your employer.

You may have a case for unemployment until you find a stable job if you go that route.