You're right to want to minimize your compulsive physical behavior in the workplace before it bothers your co-workers, but I hope very much you can also give yourself credit for the work you're already doing.
Anyone who wants to pretend that your Huntington's disease is an invention is someone who does not have your best interests at heart.
I do not think it is selfish to want to donate a kidney "only" to family members.
There are alternatives to pregnancy if you want another child.
Tenancy laws can be so complicated; I want to make sure OP is protected as much as possible.