Well Dave I'd have to say being around mold constantly would make your immune system work too much overtime, which could end up making you susceptible. Some people are more sensitive than others...
Do you think you parents are affected then? Have they the same symptoms as you? Have you done any clean-up to try and get rid of the mold? You almost need an expert to find out anything for sure... It's hard to clean what you can't see though right?