Bread, pasta, rice, cookies and such are caloric
foods. You should avoid sugary
foods because they may worsen burping and flatulence. If you have iron or B12 deficiency it's not likely you can correct this in short time just with foods, so you'd need to take supplements.
So, right now you are not on vegetarian food (chicken nuggets)?
If you're prepared for one 4 day elimination diet trial, you can try it, but what are you prepared to eat (or not) rigt now?