Hi welcome to HCM... As you are taking stress , according to history first it seems to be simple functional bowel disease or irritable bowel syndrome.... So try to avoid stress.If needed psychiatrist consultation will be helpful... For constipation take more fiber food like whole grain , wheat bran , apple , carrot etc... Psyllium like bulk forming agent helpful in your condition... If diarrhea there then maintain hydration... Probiotic can be given... Now if still mucus like substance in stool get your stool examined for parasites infection like giardia , hookworm and round worm. If needed albendazole given... If needed stool culture can be done and accordingly antibiotic given... Here candida seems less likely as you are suspecting... Excess fatty food avoided because bad fat sometime pass undigested in stool. Take care... Consult gastroenterologist with keeping my answer in mind... Dr.Parth