Are you in the US? You can have your doctor prescribe domperidone (motillium), I have gotten it through the mail without presciption. I can give you the details if you want.
How old is your lo? You may want to nurse when he is sleepy, he may be more willing to accept the breast then. Do you have access to a lactation consultant? Or you can try to find a La Leche League, they will be a great support to you, and there is also tons of info on their website about relactation, laleche league.org.