Unknown Parasite, fatigue & weakness; meds failed.

Hi there, I've recently been travelling across Thailand and Laos. I developed food poisoning in Laos, I was sick once and had loose stools. That was 2 weeks ago. Since then I have had some loose stools but I am now going regularly with no fluid. I have been feeling extremely fatigued and I'm having regular mood swings, I've start crying for no reason at all. I was prescribed azithromycin which I took for 3 days which didn't work, now the doctor has prescribed me metronidazole 400mg; I have finished the course with no avail. . I had a blood test, everything is as it should be. Sometimes I get abdominal pain but I'm eating well, drinking lots of fluid, no fever. I can't go out of the hotel without feeling tired, even though I am getting 10 hour sleeps with a 3 hour nap during the day. These symptoms are very similar to what I got last time I went to Asia, when I arrived in Australia I was prescribed metronidazole and azithromycin combined at it cleared up. I can't help but feel this is a parasitic infection, but surely the Antibiotics would have cleared it up? If anyone could shed some light on what this might be and / or how to treat it I would be extremely grateful. Perhaps someone else had or has similar symptoms? Thanks in advance.