I assume you're watching the real-time one. You can see an overview of the total unique visitors under Audience tab. That is a more reliable number to follow as it shows the different visitors that watched you.
To get it to work is strange. You simply post the ID in the YouTube Advanced section named "Google Analytics account ID". It's a short code with "UA-00000000-0" that you post into it. The analytics will not link immediately but it should report pretty soon.