Is my rapidly failing foundation dangerous?
I think you need to get a structural engineer out there ASAP to investigate; I would be worried too!

Your city's by-law office might be able to refer you to someone who can help.

It might also be worth getting in contact with your insurance company - they might have their own engineer come out.

If you think it's really about to fall over you might opt to call the gas company to come shutoff the gas - the last thing you need is a fire added to this.

You need to make a judgment call on whether to stay in the house while you determine what's going on.  Being dislocated at a hotel is not fun, but if your life is in danger, its a small price to pay.  If you do leave, turn off the water and electricity too.

Good luck!