Well, I don't know, but DS was a lot like that too. I was working full time till 11 months, so he had to spend a lot of time with the nanny and wasn't always very happy about that. He'd scream and demand his mummy a whole lot when I wasn't available up till 18-odd months I guess (I can't remember exactly). Not if I wasn't there, but if I was around but not totally available to him.
Things were a lot better once I wasn't working full time. Now when I'm working he's generally quite happy to play with the nanny and loves his 2 days at daycare. He just grew out of it.
I can't really tell you if our situation is the same as yours. Maybe because I was working we did have 'attachment' problems - maybe it wouldnt' be surprising. I know DS was heaps happier once I stopped working. And even now he loves it when we have mum & DS days. But then isn't separation anxiety normal...? It tends to come and go and settle around 18-months-ish, I think (though I'm sure it varies a great deal).
For us the only answer was to give him as much as I could. DH did a lot when he could, but we've also had lengthy periods when only mum would do and DS would scream the house down if DH went near him. So I'd take time out from work for cuddles when I could. We spent pretty much all our time together when I wasn't working (and espeically when he was not keen on daddy). I slept with him. I don't really know what else I could have done


On the sleep thing, have you tried actually sleeping together? Might be a way to get some more sleep (sorry, not on topic exactly I know)