I don't know of any neighborhood in Murphy where the values have dropped that much in the last few months. Which community are you located at? Get a second market analysis done ASAP.
It sounds like you are building a custom home so I am sure that the builder will be willing to work with you on the closing date. 30K was probably for upgrades. If you are downsizing, you may want to offer sone incentives such as including the media room equipment in the sale etc... to attract buyers.
Our home has alot to offer, 5 full br 5 full ba -almost a full kitchen upstairs, huge courtyard to fit alot of cars,,etc, etc. The downside to many buyers is it backs into Betsy. - which was never an issue for us. Its very quiet here and only residential. My pool is private, even if you tried to look in my yard while driving by, my yard is pretty secluded.
I truly love this home and I will miss it, but it is way too big for 2 people and we need to be closer to our business.
If you are using a Realtor for either transaction (buying new construction or selling your current home) I would recommend that you have them review the contract with you to see what your options are. Depending on the verbage, you may also want to consult a real estate attorney.
New homes take an average of 6-months to complete, so March does seem to be the right timeframe. However, depending on the custom features, size, and location of the home that timeframe could vary. Does your contract specifically state an estimated closing date? If so, that may help determine some of your choices.
Is you current home on the market now? Was it on the market when you decided to purchase the new home? If you signed the contract to purchase the new home contingent on the fact that your previous home sold, you may have a way out of the new home purchase (but you will lose that home and be stuck with your current home).
I sincerely hope that you have a professional Realtor to look to during this time, as their guidance will prove to be very valuable as you proceed. Good luck!
Coldwell Banker Jane Henry Realtors
Chaning lives, one home at a time