Short on sleep

Living in this community, we tend to get relaxed about how safe we are. We know our neighbors and generally look out for one another. We know when an unfamiliar car is in a driveway (one neighbor asked who was visiting with me after th truck had been in our driveway for a week or two, back when it was an extra vehicle). It's a dog friendly neighborhood, which has pluses and minuses...no one notices a barking dog all that much, good if the WonderMutt spots a cat he wants to get to, but not so much interested when the neighborhood hounds get wound up. Too much crying "wolf", I suppose. And it's an older neighborhood, so we're usually the last house with lights on...no one's up to notice anything unusual at night.
We had gotten lax about things like being sure the windows were locked, we locked the vehicles at night, even occasionally forgetting to lock the back door (which turned out okay when we were out of town and gave the cat-sitter the wrong key, but won't happen again). I say "had" because Tuesday night, while the front of the house was dark and we were getting ready for bed, we heard what sounded like someone trying to open one of the doors.
They were both locked, so the first thing I did was check what kind of mischief the furry kids might have gotten into. The spooky Boo cat was with me, and the WonderMutt was in the bed, so I started to get nervous. I turned on the outside lights, and then started checking all the windows. After a few minutes, the neighborhood dogs cranked up, and I decided to call the police, using the non-mergency number, to ask them to cruise through the area once or twice overnight.
Have to say, we've got good police here in Beaufort. In just a few minutes, there was a knock at the door, which set the dog off. They looked around the house and didn't see anything, and said they'd keep an eye on things throughout the night.
I still feel safe here...as long as there are no strange noises. The dogs started barking a few minutes ago and a car alarm went off, and my heart started to beat faster. So I guess I don't, so much, feel as safe as I did. I haven't been sleeping well the last few nights, I think because I'm listening in my sleep for something to happen. And I have to wonder, too, did I hear what I thought I heard? Is there anything to this?
We've agreed that if anything else happens in the neighborhood, or if I continue to feel a little uncomfortable, we'll take some simple and fairly inexpensive precautions, some things we'd have done before now if we owned instead of rented the house, since we haven't wanted to bother the landlord with little things (even when we're paying), knowing that there have been some major repairs, and there are still some significant problems.
It was probably nothing. It might have been someone looking for an easy chance to grab some food and maybe the computer. There are lots of houses in the community that are empty at least part of the year, so you'd expect some opportunistic break-ins. There's no one in the neighborhood who likes to party late, so I don't think it's someone who just tried the wrong door, something that happened from time to time when I lived in bigger cities. But it was probably nothing--some other noise that I mistook. Even so, I'm a little spooked.