Oil pressure light on

Can someone help me? , I have a Daewoo Nubira Station 1.6, yesterday the light pressure light on the board was turned on when it was in reling, accelerated and turned off, but began to sound a bell in the engine, it became more noisy than normal, when you arrive home, check the oil level and it was fine, but you found an oil leakage by the valve cover Spark plugs and filters, when changing the spark plugs, they were with oil, they might get wet by the loss that the packaging had and the head was filled but he is worried, provided on and part to the touch but I keep the light of oil pressure on.
It can be if the oil level is fine and changed it little.

thanks beforehand

How,

may the strainer in the carter be covered or the pump stop working. You shouldn't use the car like this !! Verify with a mècanico meter (Barometro) the oil pressure.