I'm very sorry to hear about the situation you're in. If you believe you were terminated due to your discrimination, I would contact an attorney in your area as soon as possible. Many offer free consultations, so maybe start there. It sounds like your employer is not willing to give you reasonable answers to your inquiries, so an attorney might just be able to get some of these answers out of them.
I have a guide on my profile that explains some general information about how to work with a disability and the responsibilities of employers. I would take a look at it, I hope it helps.
There are a lot of facts that need to be fleshed out before an accurate assessment of your case is done. Try to meet with an attorney in your area and provide them more information about your situation. Best of luck going forward.
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It sounds like you have a potential claim. Every case is different, and disability discrimination cases can be difficult. But many of them can succeed. I strongly urge you to talk to an attorney licensed in your state that represents Employees in these matters. Also, you can file a complaint with the federal or state agency. Don't delay. In most things, you must file in 300 days. Some states are shorter if you do not have a state agency that cooperates with the EEOC.
Consumer & Employment Law Center of Wisconsin
To add a little further to what the previous attorneys have stated, it is fairly difficult to win discrimination cases and they are highly fact-specific inquiries so discuss the matter with an employment lawyer immediately while your memory is still fresh. This is unfortunate and at least apply for unemployment insurance in the interim.