Rear passenger side suspension sag?

[BearClawz]

Last night while I was driving to work it felt like my hummer was leaning to the right. When I got out and looked the front was fine, but the rear passenger side is sagging a little over an inch (used measuring tape). I don't have air ride suspension so could it just be a bad shock? Is there anything I can adjust to fix this problem?

Thanks :beerchug: