Knocking sound what should i do

What is your question?

I have a town and country minivan thats making realy bad noise and i would like and get advise from somoene i recently remove the oil filter and started it and there was no much oil coming out then i removed the oil pan and there was shreds of metal. Somebody toll me that its my oil pump that there wasent enought pressure so what should i do replace the engine or should i replace the oil pump because my minivan still runs and everything sounds good exccep for the knocking sound