Exhausted...

I'm just now 30 weeks pregnant and I am sooo exhausted. The other night my toddler didn't sleep well, so I was up half the night. But since then he has slept fine, and I have slept fine. But I also feel like no matter how much sleep I get at night I am still just sooo exhausted and cant make up for sleep that I lost that one night like a week ago... I'm irritable and touchy and always tired. Please tell me I'm not alone! I don't remember being this tired with my first.