HELP!!! Something has finally broken down!

[rino]

This is in reference to what was discussed earlier here (even though it might be something entirely different, but I doubt that):

http://www.peachparts.com/shopforum/showthread.php?t=179218

I had made everything ready for lifting the car and placing it on stands tonight, in order to look into the brakes and various other items under the car likely to be responsible for that rumbling/clunking noise from the rear... was (and am) going to do it tonight...

About an hour ago I was driving the car (luckily I was just about half a mile from where I live) and suddenly there started this constant loud grating noise coming from the rear.
I was going about 25 mph, and the noise was so loud and alarming that I pulled immediately to the side of the street and took a look under the car (it sounded like something had partly detached from the bottom of the car and was being dragged on the pavement)... But nothing was hanging and everything looked normal. I drove the car VERY slowly (still with the noise on) to my garage. I am going to take a more in-depth look tonight.
Now the car makes this noise, constantly, whenever it is moving. It is a loud rasping noise that sounds like metal grating against metal. My first thought is that one of the rear brakes might be causing it.

Please advise... I hope I didn't cause a huge amount of damage...

Thanks,
Rino