You are good. I was under the assumption that the spring was "in" the pond.
New ponds take time to have all the newly excavated dirt absorb all the water to saturation. So, in a new pond it is common for the water to rise and fall as the dirt soaks up the water. Once the dirt is saturated, then it should hold water pretty well. Ponds don't seal like a bathtub, they all leak a little - it's the nature of the beast, but you really want to have more water coming in than goes out whenever possible.
