Stomach Infection. Worst with bowel!

I ate cooked fish few days back and at night I had diarrhea. I took an antibiotic called azithromycin 500 mg with rifaximin 600 mg. Next morning I was alright and I continued the medication (azithromycin 500 mg+rifaximin 600 mg) two times a day and at night I had diarrhea again. Next morning there was mucus with loose stools. So I stopped rifaximin 600 mg and took tinidazole 500 mg along with azithromycin 500 mg (2 times daily). I felt better and continued for 5 days and I stopped azithromycin 500 mg and continued tinidazole 500 mg for another 3 days (to complete 7 day course). But after stopping azithromycin 500 mg, I started to feel sick again and on 6th day I had diarrhea with chills. So I took azithromycin 1g along with tinidazole 500 mg on 6th day and I felt better. Then on 7th day I reduced the dose and took azithromycin 500 mg along with tinidazole 500 mg and I had diarrhea again. I was confused, so I stopped azithromycin and continued tinidazole 500 mg but felt worst with bowel