I have the same symptoms you have: nausea after eating, fatigue and pain in the lower abdomen. I also have mild headaches and my face feels warmer. I was diagnosed with visceral hypersensitivity but I am wondering if I was not misdiagnosed. Could you please share with me when you find out what is causing your symptoms.
You might have a parasite. There are many different types of flukes, worms and mites that can cause this type of nausea.
See a doctor about taking an anti-worm medicine.
Wishing you the best
I think you should have an upper and lower endoscopy. You may have a source of bleeding causing anemia. Or you could have an absorptive problem and having vitamin and mineral deficiencies.