I don't have any advice, but you have my sympathy and I hope you feel better soon.
I wouldn't mess around when it came to my brain, providing I had the money or insurance, and I think it's always worth getting a second opinion or really pushing for more testing. Sometimes people can fob you off in order to save money, avoid risk, or even because they're just lazy.
If you think you need to care, don't be afraid to demand it.