Will Less Sleep Lower My Intelligence?

I understand that obviously if you don't get enough sleep your body and mind desires you seem a bit weary. I've been surviving on 5 hours of sleep everyday, and I'm grade 12. I hate that, I love sleeping, but I feel like I'm getting more stupid everyday. As if my I'm killing all my brain cells by not sleeping. Is that even possible? Can I permanently lower my intelligence by not sleeping enough?