Ford Focus shaking from the back?

I just want a ball-park hypothesis. I know I need to take my car to a mechanic to find out what's really wrong but I can't until Monday. All I can do right now is get an idea of what might be wrong here.

My 2003 Ford Focus shakes a lot from the back, making clanking noises. I do drive some bumpy roads, so it might be the springs. But if there's something else is could be, I d like to know.

Two address two possibly different issues (having worked on a Ford Focus for a few years now).
The shaking in the back might be caused by bad wheel bearings. This is often caused by work being done on the rear brakes and the nut that goes on the rear spindle might not have been torqued right. A common mistake because I have seen at least three different numbers referenced.
Rattling (noises) are probably the heat shields on the exhaust system.
Worn shocks can cause some of both of the above (which I guess is three possible issues). The shock makers suggest that shocks are only good for 50000 miles. I have seen them last 150000 miles. Worn bushings in the shocks can make the problem worse.
I would suggest jacking up at least one rear tire so it clears the ground. Worn bearings can sometimes be felt when the wheel is rotated by hand. So spin the tire. This is not a problem I would suggest driving with!
It is not the springs, well that is my opinion- the Focus I work on has 250000 miles on it and the springs are still good.

It might be bad or broken rear stabilizer bar links.
Always check the wheel lug nuts to make sure they are tight!
A broken exhaust system hanger is also a possibility.

Broken or loose strut/shock? Loose wheel lug nuts?