You can always sue, but the real question is "is there any chance that you can win"? Exactly what "negligence" is the lender responsible for?
Did they disclose all of the fees involved? Was your income / debt ratio acceptable? Did they lie to you in any way?
Unless you can show that they mislead you in some way... I don't see any hope for winning... but then, I'm not a real estate attorney... and this would be a good question to ask of an attorney.