When your car has a loss in oil pressure even if it's just a little loss in oil pressure take the oil pressure drop seriously and get the vehicle to a mechanic to check it over.
If there's no oil pressure at all then shut your engine off and call for a tow because if you continue to drive with low or no oil pressure your engine could seize up causing you to need a new engine.
An engine needs the correct oil pressure to be lubricated properly so don't drive very far if your oil pressure drops and get the car to a mechanic as soon as possible to have it checked out.
It could be that your engines oil pump is failing and needs replaced or your engine oil filter could be clogged.