1995 GP Rear Susp. Problem

I bought my 95 Grand Prix SE 3.1 liter car 2 years ago and it's had a clunk in the passenger side rear wheel compartment. When I hit even the smallest bump, it's almost like a clunking/rattle sound. I changed the struts in the rear and it didn't help at all. The mounts looked fine so I did not replace them. I don't know if it is related at all, but my first car was a 89 regal and i had the same problem. With that car I changed the shocks and put new mounts on it and nothing helped.
The suspensions seems to ride a lot lower too in the rear. If you push down on the trunk area, the car will not bounce down and back up at all. It's pretty stationary. I checked the suspension leaf to see if it had any cracks, and it doesn't. May it just be fatigued?
I'm just looking for any kind of information that anybody knows.
PLEASE WRITE IF YOU KNOW OF ANYTHING AT ALL!
Thanks in advance.

did you happen to check your sway bar make sure it's bolted down tightly. Not sure if our rear bars have end links or bushing of some sort, haven't been underneath in awhile, but that will give clunking and rattling on bumps.

thanks for the input. I'll check that when I get back home. I have no access to jacks or tools here.