That is an extremely idiotic, immature, pathetic and ill-informed reply.

That's the problem with asking such sensitive psychological questions
in a layman's forum.

The desire to eat feces is termed coprophagia.

http://en.wikipedia.org/wiki/Coprophagia


However, apparently yours is different, since you have no desire to eat it,
but merely have thoughts of it.

It could be OCD, since you appear to have an obsession with such objects,
but then OCD usually is associated with an act, rather than a thought, such
as compulsive washing of hands to rid one's obsession with bacteria.

OCD is usually treated with one of the SSRIs such as fluvoxamine, as well as
hypnosis and counselling.

A psychiatrist should be able to diagnose and treat your condition.