Ridiculous reasons I can't sleep

So, I am 32 weeks pregnant and am tired all the time. I nap all day when I can. Sadly though, when it comes to sleeping at night, it is nearly impossible. I have every intention of sleeping, but then I'll wake up with a sudden need for water. Not want, but need. Then I'll sleep a little more, and I must go to the bathroom. Then I'll sleep a little more, then I'll find myself up at 4am paying bills. Or, like tonight, I tried to sleep but instead I got up for this sudden need to brush my teeth. I don't know why. I just can't sleep, but I am so very tired all the time. Why body? Are there any other strange compulsions you ladies have to do when you find yourselves unable to sleep?