A more than average amount of mucus in the stool can be caused by several diseases; among them of course is a Candida overgrowth. Other causes are IBS (irritable bowel syndrome), bacterial infections, and ulcerative colitis. You stated that one reason you believe your problem is Candida was because of a vaginal infection; I assume you’re speaking of a vaginal yeast infection? Also, as far as your nail is concerned, does this look like a fungal infection or a bacterial infection? Typically a fungal nail infection will cause the nail to turn different shades of yellow.
If so, how long have these infections been occurring?