Above your head? That's an interesting place to put it.
Microphones work based on the force of audio coming from the source. The louder the main source of audio, the less you will hear the quieter audio signals it can record.
So yeah, if you put the mic above your head, your voice volume will be pretty low, meaning you turn the gain up and key a lot of "not your voice" audio recorded. Most mics that gamers use are designed to be placed about 6-8 inches in front of your face and slightly off to the left or to the right to help remove plosives. Turn the gain on the mic down and put it in front of your face.