not recording sound

so this problem has just started and never done this before

I load the backing track file to audacity and on the top left hand corner of the screen there is a microphone tab. I turn this up to full. Now I press the record button and as I sing into the mike the volume starts to drop on the microphone tab. When I play this back to myself, as it gets going I can no longer hear myself!

Is this problem fixable or should I be looking ells where?

Thanks
Toolless

and as I sing into the mike the volume starts to drop on the microphone tab. When I play this back to myself, as it gets going I can no longer hear myself!

So it works at first and then fades-out? Turn OFF [u]Windows “enhancements”[/u].