Help diagnose a mystery illness

[Lps1919]

6 months ago I went to Bali and got sick over there. I spent over 5 days in hospital with what they said was normal travelers diarrhoea. When I got back to Australia I saw a few doctors who did some blood tests that came back fine and a stool sample that detected salmonella. I was told to go home and rest it would leave on its own. Since I got home I've been nothing but sick all the time. I've had several tests done including ultrasound, blood test, stool sample, gastroscopy and colonoscopy. Everything has come back as fine.
I feel extreme nausea, abdominal pain and pain in my right side, changing from diarrhoea to constipation and back, no appetite not even for water I can't stomach it, headaches, fatigue, weightloss, high temperature and body aches and pains. No one can find what is wrong with me, I'm desperate for help I can't go on much longer with this.