Either you may be wearing very popular clothing or shopping from popular places, or some people may appreciate your sense of fashion and could be copying your style. I wouldn't take this as a negative thing, though. People you see could really like your sense of fashion and use it as inspiration for their outfits. There is a reason people say imitation is the highest form of flattery.
Because you are sylish and they aren’t
Once upon a time, stores sold clothing in a wide variety of colors. Now, thanks to shoddy foreign manufacturing, color choices are extremely limited. A tshirt might now come in three colors, when years ago, it came in a dozen or more.
Did you join the military ?
it's your imagination
Fans get that way!
Because they like what they see and want to make themselves feel and look good so they imitate you. It’s like seeing a celebrity trending red hair so many people who liked the look and did the same
They must love your Hamburger Helper noodle weave.