Took all of my electric guitar strings off at once now my guitar sounds weird. how to fix?

i have a washburn shadow series electric guitar (they look just like a fender strat) and i finally replaced all of the strings since they were 11 years old, but i took all the strings off at once and when i put new strings on it it sounded really bad i think i messed up the tremolo. can someone please give me detailed instructions on how to fix this problem. thanks