I just found out while browsing the internet that the property I've been renting was scheduled to be auctioned off two weeks ago. I have received no notice of any kind from anyone. My biggest fear is that I will come home and my belongings will be on the street. Is it mandatory, even in month-to-month and with foreclosure, that a tenant be given 30 days notice before any action can be taken?

Do you know if the property sold, or did the bank take it back?

You'll be given notice, just maybe not 30 days, depending on who now owns the property and what your state laws will require.

I don't know of any situation where anyone could (legally) just throw your stuff out without giving you notice, going through an eviction, etc.

Most properties don't actually "sell" at the auction, most end up being taken by the bank for the amount due. You will receive a notice, it may be 3 days, not 30, or 7 days. But then if you don't move, they still have to take you to court.