No doubt it's a good song...
...but it sounds like you copied some pieces from this other song on the Audio Portal called "Eternal" by shortguy014. That's probably why you thought it sounded familiar, because some of the music has (in a sense) already been created (unless by some weird, near impossible, coincidence you made this without even ever listening to that song, in which case, forget everything I just said). Though, never-the-less, the song is more musically developed and well executed than "Eternal".