The world is in a constant state of change. The change could be geologic, environmental, political, economic, technological, or evolutionary(organic and/or AI). The change could take years or might happen as a sudden and shocking black swan event. https://en.wikipedia.org/wiki/Black_swan_theory

But it's also possible that the change could be to your world in particular — your outer circumstances or the configuration of elements within you. While nothing visible changes dramatically in the outer world, it is possible to have recognitions, intuitions or visions powerful enough to feel the shift of your inner tectonic plates.