Body doesn't wanna rest. Why?

Courtney
I'm a server so I work late . I got home at 12 tonight as I usually do . last night I got home at 12 as well and I'm 36 weeks and 5 days. I couldn't for the life of me fall asleep I fell asleep at 5 am woke up a little before 9 am and was up for the day . i tried to nap and my body said no . any mommas out there experiencing this ? I've heard of third trimester insomnia but don't know if that's a real thing all I know is my body just doesn't wanna let me rest .