I'm so outta of it right now

I thought that Xanax and Valium were supposed to be addictive, where one has to keep taking more and more to get the same effect.  I, however, seem to be going through the opposite effect.  I I get totally knocked out on when I take it, so much so, that I actually will fall asleep in the car (with M driving of course) which I've never been able to do in my entire life.   It's not calming me down anymore, it's knocking me the fuck out.  

Like today for example, I had my morning round of pills, and now I'm fantasying about using my sick time so I can go take a nap.   No, I'm not fantasying, I'm seriously considering it.