I had symptoms similar to these a couple years ago, and it turned out I had parasites in my stomach.
I just had a look and found this info on my iron supplement...
"Ferro-Grad C Tablets is an iron supplement used to prevent and treat iron-deficiency anaemia and vitamin C deficiency when the two are present together.
Iron is present in a variety of enzymes involved in the production of energy. The added vitamin C helps the body to absorb the iron. A controlled release system in the tablet allows release of the iron over several hours and reduces the likelihood of stomach irritation."
I have iron deficiency anaemia at the moment due to stress lowering stomach acid. I'm not normal (lol) as I'm never very hungry regardless so I can't comment on that symptom. I did find this on low stomach acid though...
Excerpt from Low stomach acid: cause and effect by Kyla Schmidt...
"Low stomach acid leads to poor absorption of all minerals especially calcium, iron, zinc.1 Many of my clients complain of fatigue, or are constantly hungry despite eating plenty. Stands to reason they aren’t absorbing properly."
I have read iron supplements can cause stomach pain and nausea. I don't have issues taking but maybe I'm taking a better type of supplement. It cost a lot more and it's called Ferro-Grad C.