I love String cheese sticks - eat them just like they're meant to be eaten. Little by little and it makes you think you've eaten much more. And they have a nice favor too.
Also, cut sugary drinks out of your diet period. Or limit yourself to a glass or two a day like I do. I used to be absolutely addicted to Kool-Aid >.>
But honestly, learning to eat good foods is really just that. A learning process. If there were "good" foods that tasted like the junk foods we all love, everyone would be in much better shape! ;D
I have a severe aversion to veggies. The texture of them, and even the smell sometimes makes me vomitous. Not to like, call you a liar or anything because I don't know your situation, but I have a close friend that will only eat pizza (takes the cheese off and eats it seperately), chicken fingers, fries, snack chips, candy and sugary fruit. That's it. He's constantly going to the bathroom (like, once or twice every two hours) and having stomach problems. At first (years ago) he said he has the stomach problems because of certain foods. And whaddya know, it was the foods that are actually not too bad for him lol. He absolutely gagged when we tried to make him eat a taco or even a hushpuppy (had ot go vomit after that one). He recently went to the doctor and she told him that it's pretty much all in his head. That it's something that will NOT be pleasant and he just has to teach himself. It's not natural for your body to be averse to things that is good for it. However, it was not
made to digest things like fried foods, processed meat and sugars all the time. When he finally (if he does) decides to eat healthfully, it will reek havoc on him for a bit because his body will need to adjust, but in the end it will handle it better than the junk he's always eating now. Have you talked with your doctor about your eating habits and how that might e affecting your stomach problems?
Something that stands out to me with your particular problem is that you have a 3-year-old son. Do you make him eat the foods he should be eating and not just what you will eat so you can teach him how to eat right and not develop problems himself? I know that's who I blame for my inability to get certain foods down, my parents. They didn't teach me how good the "good" stuff can be.
What do you LIKE to eat and CAN eat so that gives us a basis to work off of for suggestions.
I know I've done wonders by just replacing kool-aid with all but a few cups of water, replacing chips with string cheese or dry cheerios/cornflakes, a burger with a grilled chicken breast, I make my pizza at home so I know what's in it exactly... etc. (you might want to check out Eat This Not That
) And like aaachiaki says, make what you eat count. High-protein foods will fill you up for a longer period of time. Getting them from REAL foods though and not supplements would probably help you more in the long run though.