When someone copies your style, it stings. It also means you have a style worth copying. Keep moving.

Being copied is genuinely annoying and also a piece of evidence. It means there is something recognisable about what you do, which is what most people are working towards and cannot manufacture. The imitation is always behind you, since they are working from a finished result while you are already somewhere else. Staying in motion is the only reply that works.

Let yourself be irritated for a while, then write down exactly what they took, because that is a description of your style. If credit matters, ask once and politely. Then put your attention into the next thing rather than the comparison.