Why do I wake up in the middle of the night to check the locks?

This has been happening for a couple of months now. I’m 20M and I have no idea why I’m doing this. I wake up and I’m in the middle of my bed in the dark, and I can’t see a thing. So I have to get out of bed, and I make my way over to my door. I open the door and make sure they’re locked, and I can feel my heart pounding in my chest the whole time. And then I close the door, and walk back to bed. But why am I doing this? I don’t feel like I’m in danger, but something tells me to make sure the door is locked.