Lethargic tired??

I am 6+1 and due early Sept. I am so exhausted dead tired that I can get nothing accomplished!! I have been taking naps and going to bed early..nothing is helping me. I dont drink caffeine, I actually weaned off of it during summer because i had way too much caffeine!!! I feel like hubby getting mad because I dont have housework done when he comes home and my house is getting messier and messier! He doesn't say anything because I have complained about how dead tired I am..but I still feel bad! Anyone else having this level of tired!???? Any suggestions other than caffeine??