The reality is that a year ago, you reevaluated everything and made a new committment:
Now, you are saying that you were wrong.
No Bank, especially yours, is going to give you another chance.
The best you could hope for is to ask the Loss Mitigation Department if you can do a Shortsale; this will give you more time and lighten the impact on your credit score.
They will ask you for a HARDSHIP letter, detailing your "circumstances".
Enlist the help of a Realtor and LIST the house before you send the letter. Include a copy of your Listing Agreement, a CMA, and a letter authorizing your Realtor to work with your Lender.