My ipod sits on the charger all day and when i take it off it says that it has a very low battery and beeps?

i had it for about a year and i treat it very well. it hasnt really held a charge for about a couple months it lasted about 1 hour on a full charge when it should last 14 hours! i dont kow wat is wrong wiht it can any body help please? grrrrr i love my ipod with all my heart and i dont want it to break cus i absolutly LOVE music sooo please help please