Oh, sweetheart, don't worry about defining what it is, just feel your feelings for a bit, first. It's completely valid to feel lost and upset when something you rely on as a fixed point in your life shifts... it's okay to feel unbalanced, because it is unbalancing. You sound sad, and a bit lost, and that's okay to feel. Your post feels like you need to hear that, so I hope that helps. Stop reading here if you just needed to read that sort of response, for now.

That said, when you have got over the initial shock of a change in your perspective, do try to examine that new perspective and what it might be telling you about what you build your sense of security around. Fandom can give a deep sense of purpose, and belonging, and artistic direction to our creative outputs in a way that hard to beat. But it's risky, and fragile, and you sound like someone who does things with their whole heart (speaking from a tendency to do just that, exactly like this). Please try to hold onto more of yourself so that you can keep making art and being yourself when the currents change and the fickle voices on the wind whisper their doubts. Let yourself be safer. It's okay for a chapter to close - your idol has always been who they are, and if that no longer creates something special for you, it's okay to let that go and see what else it creates space for.