it is possible that it could be the water you took at the local creek that might bring the problem i would suggest you get your stool test
for schistosoma ova and other parastic infections,
you should get it tested for increased mineral content, you also need to see if you have anal swelling which might lead you to release some whitish substance as well called hemorrhoids,
would suggest get seen by a specialist and be throughly checked up and given any medication to alleviate your symptoms.
hope to have answered your query
get well soon.