The interconnected computers were a problem for me to. I did exactly what you did. I complained of mites for about a year; then I started complaining about worms.
At this point I got the Delusions of Parasitosis diagnosis.
It may help to go to a doctor without giving them any previous medical history.
I finally got the test I wanted in an underhanded way. I went to an OB/GYN for an annual test. Then I calmly asked for a Strongyloides Elisa. He had no clue what strongyloides were, so he just ordered the test I wanted from the lab I wanted. He didn't ask any questions.
After I got a positive diagnosis, he couldn't treat me and couldn't find anyone (didn't try very hard) to refer me to. He just said, "Well, you're on your own".