I agree with JiMerit's water pump speculation (fan belt, even, depending on the sound of the "squeak").
I'd be careful running the engine.
The 0 oil pressure is big a concern.
I'd disconnect the oil-pressure gauge sender-line at the block, and crank the engine (or, VERY briefly run the engine) to see if oil spurts out the block.
This does not assure oil flow throughout the block, but it says the oil pump is at least minimally OK.
Maybe someone has a safe "quick-check" oil-flow suggestion?
