SCARY drivetrain noise, please help

[Evan Manaresi]

so last night, I decided to lock up the center diff because I hadn't for
a while (what the heck??!!) I turned the knob to 1, felt and heard a
thump, and then there was a clank, clank, clank... noise, sounded like
it was coming from the front of the driveshaft, maybe even in the
transaxle. It was loudest when I let off the gas, and the engine was
kinda slowing the car. Also, when I went around a slow turn, it felt
very stiff, almost like the rear was locked too. And when I turned the
knob to unlock it, it didn't unlock for a long time. ANY IDEAS, PLEASE
help, I am really scared. Oh, yeah, also when I brake hard, the car
pulls to the right some, I figure this is a combination oif brakes and
bad alignment, but any other ideas would be appreciated.