Bristol Palin -- Second Out Of Wedlock Pregnancy ... Sorry Mom

Bristol Palin just threw cold water on what's supposed to be a joyous occasion ... being pregnant.

Palin's in the early stages of her second out of wedlock pregnancy, and this time she's full on grumpy, saying she knows it will be "a huge disappointment to my family, to my close friends, and to many of you."

Bristol says she's "trying to keep [my] chin up on this one."

Sarah Palin's daughter was engaged to U.S. Marine veteran Dakota Meyer, but they broke things off last month. Bristol didn't say if Dakota's the dad.

Bristol was full of piss and vinegar, saying, "I do not want any lectures and I do not want any sympathy."

She famously had her son, Tripp, with Levi Johnston in December 2008. They broke up a few months later.