I have such a hard time telling flare symptoms from viruses and the like to tell the truth, so I hear you on not knowing when to go to your GI. Personally, this weekend I came down with something horrible (I am thinking it was some sort of virus but, not totally sure). I was having BM's like those near the end of your colonoscopy prep, you know the ones that come out yellow with not much in them for about 3 days I had leg and stomach cramps, along with the terrible sweats and of course no energy. I finally did call my GI, she said that it was probably just a virus or something I ate, but regardless wanted to do a few labs. Seemed quite reasonable to me, especially with the year I am having. Three hospitalizations since the start of the year..yay me. They didn't fault me at all for calling them, just wanted to make sure I was okay.
Long story short, no matter what you are thinking call your GI. Most likely they will agree with you, but may want a few tests done just to make sure.