Where should I look for my kitten?

As of about 9am today we couldn't find our 5 month old kitten, Ruby. She could be sleeping somewhere in my house (she's in a phase where she'll just get knocked out, sleeping in random places for hours). I've checked cabinets, closets, the basement, the ceiling, behind furniture, outside, etc. 

I'm really worried that I might have let her outside early this morning when I was looking for something on my porch. She's been on walks around most of our yard before so she knows her way around for the most part, but if she is out, there's a lot of investigating to be done. 

I tried ringing the bell on her favorite toy, shaking her favorite treats, etc. I don't think my mom let her down into the basement, and I don't think I did either. 

I'm fully aware that it was very irresponsible of me to let this happen but (even though it's not really excusable) I haven't slept for a few days and I get really loopy when I don't sleep.

My mom and I are really worried, what can we do?

Answer

Kelvin:

it will come out when it's hungry