Where's all the oil? Driver's side behind the wheel?

If so, it might be a cam seal or a crank seal. 90% of mechanics out there will replace them if they see them leaking. If they were replaced, it's possible that one of them could have been damaged, or installed incorrectly.

If this is your problem, the bad news is that all of the labor (except for the water pump) has to be re-done in order to get to it. See what gaskets were replaced (check your receipt) when the job was performed.

If it's coming from the timing cover, my bet is the crank seal... but don't rule out your valve cover gasket because oil leaks down, and the valve cover has to be removed to get the upper timing cover off.

Get a small mirror and a light and look for oil leaks on the back of the block, too. Look for oil "trails". Hopefully your engine is clean enough to find them.