Have you ever felt your gut tighten the night before a meeting, before anything's actually gone wrong? Most people call that "anxiety" and leave it there — but that word is doing far too much work and hiding at least four different things. In Part 1 of a new 3-part series, I unpack what anxiety actually is, how it differs from acute stress, and why IBS symptoms and anxiety can end up locked in a self-reinforcing loop. If you've ever googled "anxiety" after a hard day and come away more confused than when you started, this one's for you.