Might be wasting your time and energy trying to deal with traditional medical clinics. If you want real help maybe contact a head of an infectious disease department somewhere and tell them what you're dealing with and see how they respond. If they say something like " parasites are rare in America or to do a corporate lab stool test" then you are likely wasting your time.
Also even if they could get a diagnosis maybe they'll give you a day or two of medications which likely wouldn't cure anything. As for neurosuergons it shouldn't be so hard to get an mri from a doctor just say you have really bad headaches or something. If it comes back clean than most neurosurgeons probably wouldn't do anything anyway.