when i made it there was a lot of extra batter. is that bad? what should i do with the extra batter?

It may be your pie shell was a bit smaller than the one used for the recipe. That would have left you with extra filling. No sweat, because you can bake a custard filling without a crust. Generously grease a baking dish with butter, a size that will hold what you have left so that it's about an inch deep. Bake it in the middle of the oven at the same temperature, until it is nearly set, but the center will still wobble. This will give you a bit of extra custard to enjoy as well as your pie.