Usually you get an awful lot of noise when a flexplate goes.
Those bolt holes is what mounts to the crankshaft itself. What you have is a broken flexplate at the crankshaft. No, your crankshaft isn't broken.
You have 2 options. Either drop the trans out and replace the flexplate that way, or just pull the engine out through the top and replace it that way. While you are in there, you should really think about replacing the rear main seal. It'* only a few bucks. Might as well do the oil pan gasket too.