All the engine oil completely leaking from my B16A2 engine after a rebuilt.help?

I recently rebuilt a B16a2 engine on my Honda civic si 99. I got the head rebuilt and cut but not the block. I only replaced the pistons, crank, rings and etc. The block itself stood the same with no recut or nothing. Once I had everything together the engine started prefect and was back alive but all the new oil leaked to the ground and was force to turn it off. My question is why did all the oil leaked? I know it was not the pistons, crank, or other internals. And could had been because of the cheap thin head gasket from ebay that came from china or because did not change the head bolts? Or possibly both? Help.
Added (1). I just dont want to take off the whole engine again and take apart the whole engine or send the block to be re cut at a shop. I wasted alot of time and labor.

Read more: All the engine oil completely leaking from my B16A2 engine after a rebuilt.help?