Well, in my opinion, if you haven't got your own flow, or a rare flow, no one will pay attention to you. Hence why I sound old school. You don't hear many like me anymore...
You shouldn't listen, just be whatever you want to be. You cannot just easily change your sound and the type that you make. But good luck w/ that have fun !!
I personally cannot have this problem being that I can't even do a good impersonation of him in the first place. Try rapping to beats that force you to have a different flow or voice, for instance "Da Goodness" is a great instrumental to try to write to.
One good way to have a unique flow without copying the original song (which i sometimes do have a problem with), is to start writing before you listen to the beat, then match the words to the beat. I know, this is often a bad idea because you should write lyrics to a beat not a beat to the lyrics. BUT I usually make exceptions (if it turns out good that is ) You could also try just speaking and then working from there.