Mouse sensitivity dropped?

When i was just browsing the web, doing nothing crazy or anything. Just the usual stuff playing minecraft now and then my sensitivity droped! Like crazy. It became so slow i have to now use the fasted mouse sensitivity and it still doesn't suit me, its annoying me so much and i spent a fortune on this mouse. Is there a way i can get it back to normal again?

Try changing the batteries… That could be causing the problem.