I had the same problem. I spent the last 3 years of my life only drawing anime and refusing to try out any other art style. I would recommend trying other styles, not necessarily to completely adopt that style, but to get a feel for something unfamiliar. What I do to discover a personal art style is to choose your favorite artists and take a little piece of their style, and make all those pieces into your own style. For example, I like this artist's coloring technique, and that artist's way of drawing eyes, and I simply take what I like from different styles to create my own.
Itīs all cartoon styles. Not even that, just a very limited sampling of cartoon styles. Don't worry about it. Do what you want, there is no right or wrong way as long as it looks good. It's always important to keep studying the fundamentals I think.
Thanks! Yeah, I'm just working on getting looser, fluid poses, more movement to them, working to have less trouble drawing full body people moving(thanks posemaniac random pose generator for practice!) and sketching here and there in a different sort of style. I'll get there eventually. *phew*