I Have Ulcerative Colitis And IBS. I Have Been Suffering

I have ulcerative colitis and IBS. I have been suffering from loose stools, stomach cramping, occasional nausea and fatigue for the last 5 days. How do I know if this is a colitis flare or an intestinal infection or an IBS flare? I was feeling better then went for a walk this evening and it was apparent to me that I just don't feel well. I am a 64 year old female/