Can Abdominal Pain, Nausea, Diarrhea And Dizziness Be A Sign Of Ischemic Colitis?

My husband (age 34) was diagnosed with ischemic colitis in December 2013. Had a repeat colonoscopy in April 2014, which was negative. He has IBS with constipation and regularly has stomach cramps. Yesterday and today, he has had abdominal pain (scale of 7/8), nausea, frequent urge to have a bowel movement, and when he is able to have one, he has diarrhea. About an hour ago, he was dizzy and his hands had tremors. He does have chronic migraines, and although he takes imitrex injections periodically, he has not had one in the last week. He also takes Depakote as a preventative for his migraines and Effexor for depression. Question: Could this be the ischemic colitis again? Unless pain becomes intolerable, can he wait to follow up with PCP or GI next week, or should he seek immediate medical attention. I didn t like his hand tremors and how pale he became, but that did pass within twenty minutes.