I would focus on the levels you can see in your video editor. The problem might not be your music at all, but your vocal tracks.
On vocal tracks, I usually add a multiband compressor to push all the vocals to around the -4.5db mark. Once you have that down, I'd start adding music with a consistent intensity. (For instance don't add anything that speeds up, gets massively louder, etc...). You might even want to play around with a compressor on the music too, but for me I just do it by ear, dragging the volumes on each clip as I listen.