Exhausted & work

Kelly
Help! I am an ER nurse at a level 1 trauma center so because of that our ER is CONSTANTLY busy. I'm 11 weeks 2 days and exhausted allllll the time. I'm finding it hard to make it through my 12 hour shifts. I have four in a row this weekend and I don't know how I'm gonna make it! Anybody have any secrets for extra energy??