Low Oil Pressure, Oil leak, Check Gauges light on on 1999 Chevrolet Express 1500

My 1999 Express 1500 conversion van has a problem where it has very low oil pressure at idle, when coming to a stop, and any other low rpm status. This does not happen during the first 2 or 3 minutes while the engine is warming up, where the pressure seems higher than normal. I have recently had the oil changed, but the problem started before that. Also, oil leaks at higher than idle rpm, I can't tell if it's coming from oil pan or elsewhere, but it's dripping on the exhaust crossover pipe. Any answers? Thanks.

You need to have a shop trouble shoot this because if the oil pump is failing it will destroy the engine with low or no oil pressure and its a lot cheaper to change the pump than the whole engine and you never know it might just be a faulty sending unit and you can find a shop here