OK so my friend and I both remember this cartoon movie from when we were younger.we are seventeen now so we are thinking about 12ish years back. It's a cartoon movie about little animals of some sort, either mice or chipmunks or some other animal like that. And a gas truck spills on the road by the forest they live in. one little girl gets sick and her friends set of on a journey to get her medicine.
That's the majority of the plot we can remember. The cover is the animals in a walnut shell they have put a leaf sail on to make it fly.
Can anyone help us please?

I think this is the movie you are referring too...

Once Upon a Forest

Once Upon a Forest - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Once_upon_a_forest)

[It's called Once Upon a Forest. It's an adorable movie from my childhood :D