My toe was so painful, I could barely walk, much less continue training for a marathon. It was swollen to almost twice the normal size, and I knew something was wrong. So, I went to a podiatrist, who diagnosed overtraining as the issue. He gave me shots and a prescription (which helped in the short term). But, he misdiagnosed my underlying illness. It wasn’t overtraining, it was psoriatic arthritis (an autoimmune disease)…