I'm exhausted. Like EXHAUSTED.

I'm 15 1/2 weeks on my 3rd pregnancy and I'm am just wiped. I get the kids to school and come home and take a two hour nap and I'd say that's 3-4 days of the week. If it's not two hours, it's at least an hour nap everyday. 
I have been sleeping terribly this entire pregnancy. I will wake up at 3am and just not be able to fall back asleep. It's awful. This happens quite a bit, but even on the nights of great, uninterrupted sleep... I'm just beat. I don't remember any of this happening with the last two. Is there hope?!? Am I not alone here? It's making me depressed. We are pretty physically active, we walk the beach a lot and ride bikes. I take the prenatal and fish oil and magnesium. 
Please any suggestions?! Or hope. 😩