Micaela Riley knew something was wrong. At just 15, she was battling a baffling mix of symptoms: thinning, brittle hair; a missing period; crushing brain fog and fatigue so severe she would fall asleep at her desk in school. “I was rapidly gaining weight, despite eating super clean and working out six or seven days a week,” Riley told The Post. “It felt like there was a layer of puffy water stuck to my body, kind of like the Michelin man.” But when she went looking for answers, she hit a wall. Riley said she was repeatedly dismissed by doctors, who insisted she was healthy and suggested the symptoms were all in her head. A social media trend online posits that women have two options: “become a bitch, or get an autoimmune disease.” NY Post Years later, she finally got an explanation: Hashimoto’s disease , an autoimmune disorder in which the body mistakenly attacks the thyroid — the butterfly-shaped gland in the neck that helps regulate metabolism, energy levels and hormones.…