Why do you still remember what you paid for? Forget it! Inflation-adjusted price will not come back to your purchase price for a long long time…maybe 30-50 years from now we will have another housing bubble, but no way in near-term.
What you need to look at right now is how much you are underwater, and if you bail, what the rent payment is going to be? And how much do you value keeping a payment promise that you made 3 years ago?
Forget about the past, look at your current and future situation.