Symptoms sound typical of Giardia infection, especially the greasy and undigested stools. Giardia will block intestinal absorbtion, and sometimes can travel into galbladder if the parasitic load is bad enough. However, if you have been exposed to fecal matter, it could be multiple infections. You should see your physician for a proper diagnosis. They will need stool samples, usually taken in 3 consecutive days, to check for eggs/parasites.