doesn't sound good but charge it again and unhook one side of the battery.If it's down again it's all over. When ever I am going to leave one sit for an extended period I always unhook one side. Especially in freezing weather...you leave a map light on or something and it runs down when it's below freezing and it's all over.

A battery will hold a full or nearly full charge for months given no draw against it. But they can develop a condition internally that will drain them,limit their capacity ...etc....etc...