Knocking from engine

Okay, so there is a knocking sound from the engine that just started last night after the car had shut off on me while driving home. I made sure to check the oil level and it was good. Then I checked the coolant level and the reservoir was empty so I added coolant to it and it had start up but was driving sluggish and I heard the knocking sound. So after I called my mom and let her know what happened she told me to drive it straight home and so that is what I did. And the car shut off on me a couple of more times and was just like losing power as well. And that is when I noticed a unusual symbol that I never seen before and it showed an oil can over the coolant symbol and I just did not know what it could be. But once I got it home she wanted me to back it into the drive way which I could not because that is when the car would not move in reverse or drive. Need help because I truly do not know what it could be.