Here with you. I have experienced this treatment without the words projected onto me multiple times. Seems many posters here dealing with parasites have. We are not trusted by doctors. They often have Ego issues and when you insist you have parasites, they go into "heal-digging" mode - contest of Egos they think. Right/Wrong - when all you are doing is asking for help and sharing what you know to be TRUE- The TRUTH. The Truth like many things in life is ridiculed, rejected and then finally accepted. Wonder when we will get to the "acceptance" phase and out of the Dark Ages in identifying/diagnosing and treating parasites. In fact, this doctor is committing medical gaslighting and neglect/abuse. If you ever get diagnosed accurately, I would sue the hell out of this doctor and/or the hospital for justice and to promote awareness of the mistreatment we are suffering at the hands of neglectful, lazy, egotistical ,poorly trained doctors in parasitology (yes, that includes most infectious disease doctors I have met - all by the "medical textbook" - don't think outside of what they are trained).
They look at you incredulously and also insinuate that if (if you are luck/fortunate enough to get a dose prescribed) an anti- parasite medicine (the one/two pills they give you) didn't work, then that must mean "you don't have parasites." Bull****. Roll eyes here. Seems it is very difficult to find doctors trained in parasitic infection behavior in the human body, diagnosing them, and treating them- long term - not just 1/2 doses and then insinuate or directly say you are delusional. This doctor you had is the worst - directly calling you this and not running any tests. Some run some tests, but labs are untrustworthy (methods, time spent looking, stool analysis methods-not comprehensive, etc.). Doctors look at labs and look at you still trying to stand up for the TRUTH of what is really going on with you, and use that as evidence in their heads that you are delusional.
There's a whole chapter on "Delusional Parasitosis" in their Medical books when trained. If you don't fit anywhere else and you even say the word parasites, many will put you in this box - either after tests are run and you insist you do have them, after only a few tests or 3 or less stool samples, or without any in your case. They don't look at you. Then again, this is an "invisible illness" that is very difficult to correctly diagnose as you mentioned. I have read by some that you must go out of the country to get proper treatment and diagnosis like Mexico or a developing country where they are more familiar with parasites. This costs $$$ though of course, but generally less expensive anti- parasite drugs there and better trained doctors in parasite infections.
There is Dr. Simon Yu - Integrative Functional MD in St. Louis MO I have read that some have success with, but be warned - very expensive. I called to check prices once when considering going- $700 for first visit about and then more depending on what other tests he deems necessary to run plus costs of anti-parasite drugs he procures without Wester Medicine approved pararasite infection diagnosis. Uses homeopathy and Bioenergetic analysis which is great too. It is hard finding a doctor as you are experiencing for this serious chronic under/undiagnosed issue - even hard trying to use insurance.
Most that specialize do not take insurance. Which I understand, but then we who have been suffering are becoming drained of cash due to some of us not being able to work since this chronic infectious illness has taken over our lives with symptoms, research to get better, and research/capsuling/etc. on trying to get better with supplements we experiment with. It all though comes down to SELF-TRUST. Sounds like you have this already to a degree. They are NARCISSISTIC - gaslighting you- trying to make you think you are "crazy" - projection. Typical technique of NARC type medical industry (and I found with many NDs as well in functional medicine).
I use dowsing method (with a brass dowser I bought on ebay from India) to help empower myself - first gather my knowledge on treatments and then use my intuition.