Is Nausea And Fever Related To Cancer Or Some Stomach Infection?

My 41 yr old husband had the Whipple for pancreatic cancer Nov 2013. He had chemo prior to surgery (fulferinox), then radiation & chemo (5 FU), then chemo again (Gemsidabine). His last round of chemo was July 2013. He had been starting to feel better by Oct & Nov and his last CT scan in Oct was clear of all cancer. The past month he has been having some episodes of just not feeling well as well as difficulty sleeping at night. The last 2 days he struggled with nausea, which is some what new for him. He even needed to take zofran to control it. Today he did not have any nausea but has run a very low grade fever (99.3 & 99.5). He does not have diarreha but is having frequent a d multiple BM's everyday, more than normal. He did see his oncologist last week and we have scheduled another CT Scan for the 23rd. I am just wondering if we should let his doctor know about the last few days being rough and the low fever? Or is it most likely he has a stomach bug of some sort and it isn't related to the cancer at all?