Artsy - I am sorry you are feeling so much distress. I can really feel it coming off you. I don't know enough about your history, your family member, or hospitals to giev you informed advice. Is there anyone who is very rational, objective, and resourceful who can be a good sounding board?
Even if you are "crazy," if you are an adult who is not hurting anyone, your relaitive should MYOB and possibly enjoy your uniqueness. It sounds like you have a good thing going with your adopted family. If "crazy" means you are prone to depression and /or anxiety, it would be unfair to give up your adopted family to suit a controlling relative.
Why is this relative trying to dictate your meds? Can you go to a free legal clinic and see if you have legal options? Can you send an advocate to her to explain that her controlling behavior is not beneficial, and neither is spreading the word on "crazy." And that if you really needed help, it would have to come from a trusted source anyway? Sometimes people on the outside see things about us that we don't, but there is a difference between controlling and caring. Also, sometimes, they can't move past the past and see the present as something different.
If you choose to leave, find out what you can about the new place and any services that may help you with your anxiety. But reconsider allowing yourself to be run out of town, too.
Good luck!