Am I doing something wrong?

To the brain trust:

I have had some nutritional issues in the past (who hasn't right?). I ran IM Racine (70.3) this past weekend and felt quite good until the very end. Maybe it was high temps and humidity, but I am not confidant in my nutrition plan. Any advice?

Bike: 1 serving of perpeteum every 30 minutes with 2 endurolytes. Free water too, 30 oz total liquid per hour.
Run: 1 serving of hammer gel every 30 minutes or so with 2 endurolytes. This past race, I lost my hammer gel flask 1/3 the way through the run and drank perform at every aid station (3-4 oz every 10-15 min), 1 endurolyte every 20 min, and 3-4 ounces of water at every aid station.

I felt really empty at the end and was quite nauseated for 2-3 hours post race. I am worried that if the race were longer, I was going to be sick. I am looking for any nutrition tips for IMWI in 6-8 weeks. I have finished IMWI in 2006 with no nutrition problems and 2008 with LOTS of nausea and vomiting.

Thanks in advance!