Don't worry too much, Astarte, I worked with clay for a long time before this happened -- and I'm not even sure that's why I got the fungus. I just noticed one day that a few of my nails looked "different" somehow -- kind of like part was sort of "lifting" a bit.
Went to the doctor -- she said it was the beginning of a fungal infection and suggested some rather expensive medicine -- and to try and keep my hands dry as much as possible. Thought someone might know of a homeopathic treatment. In the meantime I'm going to try doing my pottery (just a hobby, not my job, btw) with thin latex gloves on -- that should be interesting....
cheeno -- I'm not sure if this sort of fungus is the same sort as the athlete's foot type, but I'll certainly go by the site and check it out. Thanks.