Do you get creeped out when you're home alone? Is it normal to want someone around if your housemate is gone overnight?

I'm hanging out with a friend tonight because her bf is out of town and she can't handle being alone in their new house. She has a big dog, but he's more apt to give kisses to any attacker than be scary. I live alone, probably because of my extreme introvert tendencies, so I don't really get it. I'd imagine living with someone else feels like an extra safety barrier; but for me, unless it's the fella, it just means I have to wear pants. I love having space to just be me in my own squalor.

I feel bad that every time her bf is out of town she can't handle being alone, especially at night. She invited me to sleep the night, but honestly I need to sleep in my own bed. I lasted 3 hours in dance classes today, my body cannot handle a foldout couch.