Have you been tested for Ulcerative Colitis at all? It's good that they're pushing tests through quickly. I was very poorly in my late teens. I had blood and mucus in my stools, I was shaking, wobbly, very weak. I could barely eat and felt very ill. I was tested for cancer as well as many other things. Mine turned out to be Ulcerative Colitis, which although it isn't pleasant it wasn't the worse case scenario. High Calprotectin indicates inflammation which isn't necessarily cancer, it can be inflammatory bowel disease, infections etc. Please try not to worry as it could be one of so many different things but it's positive that it is being taken so seriously. 
 

It may also help to know that my CRP levels are always slightly on the high side on blood tests - I have been tested for cancer recently too as they thought that I may have breast cancer and then Lymphoma due to raised lymph nodes and a breast lump. Fortunately all of those tests came back clear too, but my CRP level is always slightly raised and I have slightly swollen lymph nodes in my abdomen which they think is likely related to the Inflammatory bowel disease. I do totally understand the worry as I couldn't bear the wait whilst going for tests and waiting for results (which felt like the longest few weeks ever). Saying try not to worry I know doesn't really help as it's easier said than done but we do have to try. I really hope that everything goes well for you and that you are on the road to recovery soon.