Sorry to hear about your stomach troubles, ElCee. Did you drink any water with your sports goo? The goo/gels are typically concentrates that need to be diluted with water either before you ingest or by drinking water after you eat the goo. If you didn't drink enough water at about the same time as you goo-ed up, then your stomach is likely to be upset by the high concentration of electrolytes and other stuff. Also, it's generally not a great idea to mix sports drinks (particularly those with carbs) and gels -- the sugars seem to interact somehow and you'll feel like you're running with a softball in your stomach.

You should also try out different energy products. Gels all have different sources of carbohydrate, and you simply might tolerate some better than others. I'm about to order a sampler pack of gels from zombierunner.com. I figure I'll try them out as I run to see what works best for me. You'll want to bring several gels (or maybe you'll prefer something like Clif shot bloks) with you for your marathon.

As far as your actual training, what plan are you using? I'm about to begin training for a marathon the same weekend as you. I'm using the FIRST program; I used their half-marathon program for a half last month, and it was excellent. Lots of variation in the workouts so they never got boring or tedious. I start in a week; my first long run will be 13 miles.

You'll be able to finish. Just remember that it's okay to walk, be sure you stay very well hydrated, and don't do anything new on race day. (I'm planning on taking my own advice; I didn't for the half and my time suffered for it.)

Hope that helps,

Don