Changed oil type--new engine noise--am I crazy?

Ive always used Shell. Last week a store had Mobil DelVac on sale so I threw that in. Now my engine sounds like it has a lot of little cheap clocks and boxes of tiny metal parts clicking around in it. Not general knocking anywhere but just like everythings a tiny bit loose or dry.

Any of you experienced something like this with an oil brand change? Should I dump the DelVac and go back to Shell?