I agree that the oatmeal could be causing some of your gas. Oatmeal is a whole grain and is not tolerated very well by some people. It bothers me sometimes when I eat it first thing in the morning.
Also, you said you're eating Tostitos. Did you know they're fried?? They make a baked variety, but if you're eating the regular ones that may also cause you problems.
Good luck!
-------------------- "Anyone can exercise, but this kind of lethargy takes real discipline." -Garfield