The oil pump has a very short chain running it from the crankshaft. Could be it broke, but that would be rare indeed.
Still you lost oil pressure. Start by checking that. You should be able to either see, or at least feel the oil pump chain, as I recall it is on the front of the pump, with your fingers. Have someone turn the engine over slowly with a bar or rachet on the front crankshaft nut and see if that oil pump is still turning.
Even if the pump turns, you may end up taking it off. Seems likely whatever you found there has made it into our oil pump and is plugging it up. I think you can get the oil pump out with the pan off.
If that is the case I think you will want to change the oil pump chain and the pump. I think I spent about $350 for the pump and chain. I replaced them a few ago with a used engine I installed. Had the engine out and intall was not that hard then, don't know about doing in the car though.