I don't doubt that you got sick, and that your symptoms loosely matched the constellation of symptoms described as Covid.
But the question, in your case and every other, is what caused the illness?
Some sort of microbial parasite smaller than a bacteria (and not observable with a light-based microscope) causing the illness is a hypothesis (not a theory, and certainly not an observation). However there is no scientific evidence to support this hypothesis.
Unless some evidence emerges to support the hypothesis, we should consider alternatives. Perhaps your family was poisoned via your food, water or air. Perhaps you were all exposed to some sort of radiation. Perhaps your family was all deficient in some nutrient (eg seasonal deficiency of Vitamin D due to low sun exposure).