I had SO many health problems.
Heart arrhythmia, exhaustion, diarrhea, heartburn, stomach ache, constant flatulence, intolerance to heat (dizzy, faint-headed) ...
Then I started eating properly .. healthy simple foods. No more white flour, sugars, soda pop. Ate vegetables, fruits, whole grains, low-fat dairy, legumes, nuts & seeds, fish, chicken.
OVERNIGHT (well, a couple of days), ALL my health problems went away.
Yes, I would say that eating well makes you feel better.
I would say that chicken nuggets are NOT healthy food ... the meat has been processed usually, but even if it hasn't there is the breading and ALL the fat that the nuggets have absorbed during the frying process. That alone can cause stomach pain, especially if your gall bladder isn't working as well as it should.
Try eating low-fat meats ... not breaded or fried. Chicken without the skin. Fish. Legumes are very good for you ... especially black beans. Legumes are high in fiber. But they don't provide AS much protein as fish/poultry do and are much higher in calories too .... and if you have any problems maintaining your weight, you might find that more of a problem if you eat only vegetarian.