Good day
Every time I eat, I feel nauseous, cold sweats, headache and very tired with no energy. Its been going on for 3 weeks, lost 4kg already, only weigh 58kg and I am 1.84m tall.

Its been going on three weeks... don't you think its time you made an appointment to see a doctor? I would have before the first week was out.

I have indeeed seen my dr, and are on medication, yet the matter seems to get worse. I'm am being treated fot a ulcer, but its not working.

Then you need to tell your doctor this... they need to know this... as everything can be related... and adjustments might have to be made or medications shanged.