That's probably how close your holding your head to the microphone, I use a handheld which is nice because i can move my body with the music to get into it a little more, but my budy sits down and rests it on his knee and bobs so i have to slap him cuz his heads allways moving away from the mic.

If your wearing headphones you can isolate the volume of your voice much easier and you pick up on how its gonna sound like when your in the middle of doing it, and if you dont like it, delete it and start again and do it right, be your own critic