Are you running any type of oil filter? If so, pull the filter element, cut it apart, and spread the accordion-pleated paper out, looking for bits & pieces of metal. If there's no big chunks, you're probably dealing with a pump failure (VERY rare) or a stuck pressure relief valve. If it didn't make any expensive noises as the pressure dropped, it's not likely you've done any major damage.
The glued-on pan speaks volumes about the quality of the rebuild, none of it good. It's easy for a chunk of RTV to get dislodged inside the pan, and find its way into the oil pressure relief valve. If it gets that far, it's also possible some sealer has found its way into other oil passages, so there could be further problems down the road unless you do a complete teardown and use a rifle brush through all the oil passages, followed by lots of compressed air.
Start your inspection with the oil filter element, and also strain the oil you drain out of it through a funnel with a coffee filter in it. If you get bits of cured gasket sealer, or metal shavings, do a complete teardown and inspection, including a detail cleaning of all the oil galleries, particularly the ones in the crankshaft.
Jerry
