I have suspected mold was a factor in your situation for a long time, because in spite of treatment for infections you continued to have a set of symptoms, and that set of symptoms can be caused by mold exposure.
Your genetic susceptibility is an important factor, IMO. Also, from my understanding (and I could be wrong), normal, healthy people in the same environment would not have positive urine test results for mycotoxins. You have or have had Lyme/co. Those 3 factors (especially the first 2) should be sufficient reason to locate the mold exposure and do something about it (remediate or leave).
Taking binders isn’t a “fix” for dealing with ongoing exposure to mold or other toxins found in water damaged buildings. Exposure has to be addressed.
That’s my opinion.
"I guess I just don't understand why healthy people wouldn't have positive levels of mold in their urine if they are continually inhaling it in the same environment as a sick person. Am I thinking wrong?"
I think it's because healthy people are able to detox the mold more efficiently which is why they don't get sick from it.