This is a problem / allergy to gluten, which is found in many products, especially wheat, After eating gluten you can have several Symtoms, including: bloating, stomach cramps, headache, sinus pressure developing to infections, itching rashes. The allergy produces swelling and a r ash in the intestines, which causes scarring and reduces a persons ability to process nutrients. The little villa that absorb the nutrients scar over and this blocks them from doing their jobs. It will eventually start working on other organs and can be the beginning of several other auto immune diseases / issues. MS! Thyroid! Liver! Kidney! It has also been linked to Downs Syndrome and the ability to get pregnant.
If you are having a lot of issues with allergies, general malaise, just not feeling well, and depression, I would try not eating flour products or anything containing gluten for 2 weeks and see if there is improvement. Be sure to read labels as gluten is as the name suggests, the glue that helps hold products together. Remember making flour and water paste? This is in many prescriptions to help hold the capsules together. It is in red licorice and a lot of cereal and pastas. It is getting easier to avoid but there is a lot of cross contamination in restaurants and the ingestion of one crumb from a roll or grease that was used to fry battered products can cause a flare up.it can be an itchy rash or flu like symptoms, with diarrhea (sometimes almost immediately), or like a really bad cold. At this time the only cure is not to eat gluten. Taking allergy pills and drinking lots of liquids can help fight the symptoms- flushing your system.
Gluten is nasty stuff and celiacs not fun to deal with.