You need to take some action if the disturbance is regular.
Is the crime rate high in your area or is it just kids mucking around? The timing is interesting. We are usually at our deepest sleep around 3.00am and that's a favourite time for intruders. Again on security, we have security grills at each window and door. They are decorative as well as functional to keep my wife happy. It's important to make sure that you still have easy exit from strategic points in case of fire.
I hope this resolves itself soon, especially as you are often alone. I really would start to do something about security, just in case.
It's unlikely that it's just kids messin' around, but anything's possible. Come to think of it, there have been break-in's in the last few months just a few houses from mine...one was at a house with a mom with young kids at home, and they were trying to break into her back sliding glass door with a shovel and pick while they literally stared at her through the glass door.