Axle bearing seal went bad

[wrcamaro]

Recently I changed the brake shoes and found the drum on one side was full of grease. Oil is slowly leaking past the seal too. When I turn the axle by hand it vibrates and makes a very audible noise from the wheel bearing area.

My car is a daily driver and I don't know how long it has been like this. What type of damage am I possibly looking at?

The car is a 68 camaro with the stock rear end.

Thanks