In the digital domain, there is much less concern for signal to noise (like there was in the days of analog tape.) You don't need to record at levels above -6db and really if you are in the -12 to -24 db range you are fine.
Regarding your track. First let me say I am no expert, but here is what I hear:
A lot of bass and a lot of higher frequencies. There is no mid range until later in the track when you bring in what sounds like an acoustic guitar (and even then its not a lot). There is probably too much bass which could be a result of your studio monitors or your listening environment (or likely both.) Find some way to add some mid range frequencies (500-2K) and roll off some of the low end < 60Hz approximately. You may need to add some instrumentation (a pad possibly) to get that mid range. Also you need to apply some EQ to the drums to take some of the harshness out of them (around 10K).
If you have the new Sonar, use the Mix recall feature to try different mixes.