To get back home from the United States you will have to follow Canadian procedures and not American ones. Forget about all this Yankee passport talking.

As long as you can provide proof of Canadian citizenship to are good to get home.

http://cbsa-asfc.gc.ca/publications/pub/bsf5023-eng.html#s2 ..
http://www.timaticweb.com/cgi-bin/tim_website_client.cgi?SpecData=1&VISA=&HEALTH=&page=both&NA=CA&AR=00&DE=CA&VT=US&EM=US&PASSTYPES=PASS&user=SKYWEB&subuser=SKYWEB1 ..

The links I have provided are based on flights, but if you can fly without a passport you can surely cross a land border as well.
For another travel to the U.S. you will need a valid passport or an enhanced driver’s license for land travel if you live in British Columbia, Manitoba, Ontario, or Quebec.

If so, this should be all you need to prove your identity.

The license is certified by the Canadian government and serves as proper identification. You birth certificate demonstrates your citizenship.

If you are concerned that you’ll need your passport, and you have one in Canada, consider having someone mailing it to you.

You can call the Border Agency once more and tell them what documents have. Get a name and record their answer.

Good luck,

Sam