I didn't know until just now that it doesn't happen to everyone.

Actually, at your age, you are probably pre-menopausal which makes everything worse. It gets better once you're over the hump but it can get pretty uncomfortable until then. Do you know if you have ADHD? It sure sounds like hyperfocus to me.

Imagine you are an ancient human, when we were still hunter-gatherers. You're out hunting and spot a rabbit. Whether your family gets to eat tonite is up to your hunting skills. You watch the rabbit intently, never taking your eyes off of it, but all the while scanning for additional prey when you suddenly spot a deer. Your focus immediately switches to the deer, watching and scanning as before. That's all ADHD is. The ability to hyperfocus on what is important to you, and just as quickly change focus to something more important (to you) at the expense of all else. It's a survival mechanism that backfires when you are a hunter/gatherer in this day and age without the skills needed for agriculture. Generally speaking, since we are no longer nomads.