You can always back up, but it gonna cost you. Depending on your contract, % deposit, and how much you paid originally, you may stand to lose less if go thru the closing and turnaround and resale yourself, with paying the sales commission (might be less than your deposit). Unlikely, but possible. Also possible that resale prices tank during this time period, so it's still a risk.
Only you can decide whether you can weather a personal financial downturn, what the best decision is. If it was me, I would go thru with it, since I signed the contract, it's just the right thing to do, plus I am sure if I lost my job, I can live thru it. But the right thing to do isn't always the best thing to do financially, but listen to your own heart, and decide what is best for you and your family, after you find out exactly what financial lost you will take that is spelt out in your contract if you decide to back out.
Good Luck,
Great3