I'm not sure about the moving lumps, but, I guess you should be checked for hernias, usually found in the groin and in the line of belly button.
Hernias are more obvious when standing and tend to disappears temporarily when lying down.
Having a low serum levels of iron is a sign of iron-deficiency anemia.
That's why you feel extremely tired or fatigue.
The cause for iron deficiency could be an internal source of bleeding like stomach bleeding, intestinal bleeding, bleeding from hemorrhoids or bleeding due to prolonged and heavy menstrual periods.
Another cause can be a poor dietary intake of iron, or being unable to absorb
iron from food due to intestinal problems (celiac disease, crohns disease).
The fact you lost 10 kg in short period can cause or add to the cause of iron deficiency.
Experiencing stomach pain, nausea after eating, along with sense of fullness during and after small meals, bloating are all described as a indigestion or difficult digestion of food.
Indigestion is a symptom of gastritis, peptic ulcer, GERD, and gallbladder and pancreatic problems.

Visit a gastroenterologist!
Marija