It seems you have already ruled out music by neighbors (if any) since you say the music was coming from you. So most likely the music was coming from your mind. Do you often have music inside? If so, was this music similar to that, or different?
Over the last years I often hear music inside my mind. I remember this starting while I was in my 20es, which is a couple decades ago now, but it has rather increased lately and I often find that I hear melodies that I am sure I have never heard before. I listen to them come out of nothing, play in my mind and return to nothing again. In a way it seems like a terrible waste. I am not a musician or particularly gifted, I doubt I could catch them if I tried. I cannot even read a musical score, much less write one, and I am not passionate about music or having a great collection of music. But on the bright side, I now realize that there is an unlimited wellspring of music, out of which composers should be able to draw beauty for centuries to come.
So I wonder if you may be connected to this same invisible world of music, and perhaps have perceived it as outside yourself because you were in an altered state of consciousness for a while. Your use of the phrase "awoke" seems to imply that your meditation causes an altered state, rather than just an expansion or concentration of awareness.
In any case, I would not worry about it - unless it was rap music.
