Ooooh, I SO know how you feel. I can't offer a huge amount of advice, because we've got the same issues, but I can commiserate!
I wrote a similar thread a while ago and lots of people had good ideas to try - I'm trying to find it for you and will post a link if I do. Sadly, not too many of the suggestions helped, but they might help you, and I found the sympathy from other Mum's who'd been there really helpful anyway, it's SO nice to know you're not alone (and also not alone in being driven crazy by it!!)
When Jacob was about your daughters age, I found a dummy incredibly helpful. Someone on here suggested it, and the people at the Family Centre backed that up, and although I wasn't keen on the idea at all I tried it and fell in love with the thing

I used to pop it in and he'd go suck-suck-suck and off to sleep, and then when he woke after half an hour I'd pop it back in and often as not get another sleep cycle. Now it doesn't seem to help for that second cycle, but it still helps him get off to sleep.
I reckon just do whatever works - rocking, feeding, whatever, if it's got a chance of working don't worry about people saying it's a bad idea - and hang in there. (I know at this point you're probably thinking that *nothing* works... I'm kinda in the same boat... but I suppose some things work a little bit less badly than others!!) I keep reminding myself that it's only a short time in Jacob's life that he'll struggle with sleeping, and that lots of other babies have had the same problems and haven't ended up permanantly damaged.
ETA - I found the thread I started, you can read it
here
Edited by Hopes