Feeling a let down

So, we have been trying to sell our old house since last October. Now, we realized going into winter trying to sell a house wasn't the best of circumstances, but you do what you have to do. We were very excited this weekend when our realtor told us an offer was coming only to get the offer and it was SUBSTANTIALLY less than our asking price. We fully realize the real estate "game", but the offer was downright instulting and our realtor agreed. We counter-offered with what we (and our realtor) believed to be a fair price and spent the rest of the weekend waiting.

Today we get a call from our realtor and the prospective buyer counter-offered our counter-offer but didn't even come up much from the initial offer. I hate to be stubborn and I realze that this is a "buyer's market" but our house is already the lowest price for a house it's size in the area. At what point do you say it just isn't worth the hassle? What is that "magic" number we will settle for? I thought when we finally did get an offer, I would feel euphoric, but right now I am just plain depressed. Now, we have another 24-48 hour wait to find out how it is going to be. In the meantime, I need to say some prayers for patience.