Possible carcinoid... Please adivse?

I am a 34 year old male that suddenly started getting some (dark, maroon colored) blood in my stool, and my bowel activity became random, sometimes solid, sometimes diarea (diarrhea), usually looks watery when wiping.  Also I started having a feeling of fullness when I eat.

I had a colonoscopy, and the surgeon didn't find anything to explain the bleeding or diarea (diarrhea).

But he did have an artifact discovered on my rectum.  Tests were inconclusive because the artifact was small (my surgeon described it by drawing a small rounded dot on a piece of paper).  It was however suggestive of a carcinoid tumor.  

Although it is very small, and thus almost impossible to have metastizied (if it is even real and not an artifact on the imagining system) my symptoms are quite similar to carcinoid syndrome, and now I am very afraid this is really a tumor and I have more of them yet to be discovered.

My symptoms are bloody stool, off and on diarea (diarrhea), bloating, heart palpatations, and a low grade fever.  My doctors are performing the urine tests and a CT scan to determine if Carcinoid syndrome is what I have.

Both my general surgeon and my regular doctor both told me they believe this scenario is unlikely and they don't expect to find anything.  However, I read the symptoms of carcinoid syndrome online, and I am now very afraid that this describes my history of bizarre health problems that they have been unable to explain.

My question is, because I possibly have one very small tumor in the rectum area, does this mean that there could well be similar carcinoid tumors in other parts of my body?  Or are the doctors just being over cautious?