If you were in the UK I would be advising you to keep a good record of all of this low-level harassment because the disability discrimination act requires employers to make 'reasonable adjustments' to someone with a disability or long term condition. It sounds like you are perfectly capable of contributing to the work of this company, if they just made a few such adjustments like part time work and reduced time pressure.

I would also advise you to get in touch with your union if you are a member, or talk to some sort of legal representative about your options, should you need to use them. Your idea of talking to an employment attorney sounds spot on to me, and I would advise you to do it ASAP. Even if you decide you don't need to take action at this stage, it would be useful to know your options and the sort of evidence they would need you to be gathering. Be prepared.

I don't know what the legal situation is in the US but perhaps someone else is aware of similar legal protection?

I would also advise you to try to get yourself referred to the company's occupational health department or provider. You can put them in touch with your neuropsych if necessary and they should have the power to make recommendations to your boss about adjustments you need to the workplace in order to function to your optimum level.

You are being discriminated against because of your condition - it is a very stressful situation to be in but I'm sure all of us here feel for you and wish you the best of luck