I would suggest you consider these suggestions:
1. Talk with a local Realtor regarding the current market value. Preferably a Realtor with Short Sale experience.
2. Contact your lender immediately and let them know that you are unemployed. If the loan servicing agency contacts you respond, answer the phone , and start a dialogue.
3. I would also look into the possibility of leasing the property. Have your Realtor give you an idea of the lease amount. Talk with a tax professional about the tax implications.
4. Try to find a room mate, someone to help share the mortgage cost. Many people are in a tough spot and need a short term living situation. Make sure that you check their credit.
From the lender's perspective, they would rank order their options this way:
1. Keep you in the house, modify the loan IF you want to stay in the house and IF the prospects of you being able to maintain current payments.
2. Keep you in the house, they might modify your loan structure to make it affordable.
3. Sell the property as a short sale, meaning you pay no closing costs, they absorb a loss, pay for closing costs
4. Allow the lender to foreclose - this is the most expensive alternative for a lender which they would rather avoid.
If you would like a referral to an experienced short sale Realtor, let me know. Good luck.