It could be that your chronic stress disrupted your digestion and gut flora, and now they both sustain each other. Stress and dysbiosis cause inflammation and inflammation is linked to depression. Since they both cause each other, it’s kind of a chicken and egg thing. I’d follow the antibiotic trail for the easiest answers.
Remember a candida overgrowth isn’t one-dimensional and is a sign of a severely unstable gut flora, containing potentially hundreds of different pathogens that can cause symptoms from acne to H. pylori overgrowth. It’s likely for that reason that no two people on this website have identical symptoms.