I'm in for some suffering

My fuel/hydration problems have always started around the 16 mile mark of long runs. If I drink or eat anything immediately before or during a long run, I develop a side stitch followed by nausea and/or tingling of my extremities and finally tunnel vision and dizziness. I have been drinking Carbo-Pro and water before my runs now for 10 days but today was the first run longer than 10 miles. I drank 6oz of water with Carbo-Pro before the run and 3 drinks of water during the run of approx 3oz each. By mile 12 I had a major side stitch going and contemplated stopping. I held on but had we gone much further I would have been dropped by the group. I am going to give it one full month of attempting to fuel and hydrate during runs. After that, I suppose I will have to adjust my goals or give up the marathon. It was good running with the group again and getting a soak in Barton Springs Pool afterward. The topless chick made her appearance and that always makes for an entertaining round of commentary.