I heard a slight knocking sound in the engine. Change eng oil & svc eng soon on

What is your question?

My engine literally felt like it was stalling and I heard a slight knock. I pulled over to check my oil because the "change oil" and "service engine soon" lights came on. It was a quart low so I added a quart. I turned the car back on and the "change engine oil" light went off. Service engine soon didn't. I was able to drive no more than 15 mph the 2 miles home. If I drove any faster the car kept trying to cut out and the knocking was loud. Help?