Ack! Hope it was just animals making noise somehow, that's totally freaky.
When I lived with my parents in NC, it wasn't long after we had moved in and I was chatting with a friend on the phone around 2am downstairs in my room (they had 2nd living quarters in their house, and I made the old computer room my bedroom, the rest of the bedrooms were upstairs). I heard something rattling the knob and glass on the back door in the laundry room, diagonally across from my bedroom. I froze, locked my bedroom door, and put the computer chair under the knob. I refused to leave the room. I knew my dad had a gun upstairs if anyone got in, but I certainly was too scared to even risk being in sight of someone to run up there at 2am - whether or not they'd see me. The next morning, my mom told me that she saw a flash light go by the bedroom window around that time, and heard someone trying to open the sliding door from the deck. She always puts dowels in the door track on sliding doors, that's what kept it closed. We had an alarm system installed a couple days later.
In Jersey, we'd been robbed while out at my grandma's house one year on my brother's birthday and my dad was out of town racing, stole ~$25k+ in jewelry, plus my mom's coats, so we've always installed alarm systems in houses. The next house we lived in would beep if the alarm was turned off and one of the alarmed doors or windows were opened (the door from the garage, the front door, and my parent's bedroom window since there was a screen house back there you could enter their room from if you used a ladder). I was home from school and heard the beep sound ... but my parents weren't home and my brother was still in an after school program. My dad made me go investigate while I had him on the phone

I brought a frying pan with me...much good that would have done

Then i stayed at my friend's house until my mom got home. No idea why the beep went off, must have been a glitch or something.
The current house we live in doesn't have an alarm, I'd love to install one, but I also have five guns in the house - a 9mm loaded and ready with hollow points, two tactical shot guns, and two 36" barrel marlin goose guns. My 9mm is in the drawer next to the bed and the shot guns are in the corners next to either side. I have no problems using them, and have investigated noises in the house (non-cat noises) with my 9mm at my side. (One time i came home from work, and heard strange noises on the other side of the house, eek). I've also thought I've heard the sliding door open before, made hubby get up at 4am with his shotgun to investigate

He keeps his .40cal at his shop, because he works in a bad area and is there late sometimes.