You've had it 1 1/2 years. So you got it in late 2005. Truck was 3 years old. And it's only supposedly worth 6-7k now?
A quick NADA estimate showed a base, no options, Silverado with 80k had an 8550 trade in value, and 10,700 clean retail.
So you're certainly a bit upside down, as you should be after only a year and a half, but not that bad...unless the particulars of your truck would drop the value significantly.
Bottom line is, lose the "I wants". You need to keep that truck at least another year and a half, maybe more, to get even. And you might never be even in trade-in value until it's paid for. Never trade....always sell it yourself.