Hey M:
I completely understand your dilemma. You have parents whom you need to believe (not only that - that's only half the challenge) and understand what you confront from within.
Here is a really good opportunity for you to put your legal mind, analysis, investigative and presentation skills to the test.
There is a way to do this. I had to (HAD to) acquire a REAL diagnosis. Whether it was to clear my head, clear my name, or clear the way for full on treatment toward the correct pathogens, etc. - I knew I was not to become one who got on the uphill battle to prove myself. I proved myself a LONG time ago, and I knew that if any health issue was to bring me down it would only be understood as psychologically imposed/stress related/work overload. I couldn't swallow those chips.
So long as you oblige your parents and follow their instructions as you pursue doctors and testing - you lose a bit of control because it becomes more chancy (the false negatives). I have not heard you so much describe anything exiting your body on a regular basis. This puts you in a tougher to diagnose catagory than me also.
But if you could find a scientist, histologist, virololgist, or specialist who works with a scope or has as a liason a collegue, team member, who looks at blood (must be a very powerful microscope - I'd research who in your area, or whereever you would be going, might be using powerful scopes) - you can perhaps set something up.
It could involve a script to have bloodwork done on parasite, fungus, bacteria, etc. - you kind of need to put it together yourself - JUST the way you would wish it would work. It could involve a lab there which can draw the blood but has orders to send to a particular lab.
These guys are out there. Not easy to find, but I assure you - when one sets his sights on something and allows nothing to compete with that vision, one can accomplish just about anything he/she dreams of.
I see this in each and every major accomplishment in my life. The biggest one being, of course, finding the right people to oversee my recovery. All else pales in comparison. But I put myself in the position where NOTHING but NOTHING could get in my way and keep me from acquiring the TRUTH about what was IN ME!
Thinking about you. Will continue to think about your situation. When do you have plans to see doctors in - was it Poland? Have those docs already been identified by your parents or are you to set this all up?
C