Try the following thing - these almost always work for me. Do ALL of these until you notice it working.
in the inventory window, find the items you are wearing. Remove and re-wear these items.
bald hair base, shoes and foot shapers
Next "change" these items that you cannot simply remove (wear a different one and then change back to the original).
Shape, skin, eyes
If that doesn't work, then change your outfit (if you are not in a Adult zone, don't get naked, others may be able to see you)
If you are still a cloud, Right Click on Body Parts in your inventory and click new Body Part
Pick SHAPE, it will create a shape named "New Shape". Wear that.
If You're still a cloud, then either something you are wearing is lost on the SL server, or there is a problem with SL. Either way, they will probably fix it within a few hours. Check the SL Grid status page http://status.secondlifegrid.net/ to see if there are problems with the "Asset servers". That's where all your stuff is stored.
I hope that helps!