How to wean my 17th month old daughter?

I feel for you, I really do. I have been there! The only thing that is truly going to work is to stop nursing completely...cold turkey. Give her a few days warning and let her know that when she cries, you'll rub her back, but that there will be no more nursing. It will be 3 days of hell and NOBODY will get any sleep for those days. But, the good news is, afterwards, she will be weaned and you'll both be sleeping better. There's no easy answer- it's really just weaning cold turkey. Just remind yourself to Hang in there and that it will be over shortly.