Hi girl, which teat r you giving your baby? You r facing a very common problem because baby are habit creatures. If they r used to your nipple, they will only want your nipple.
You can try to give him other teats to try. From what I know, Tommee Tippee is designed to b similar to mummy nipple. I heard good reviews for Nuk for imitating nipples too. you could buy 1 bottle n try if he ok with the teat n Start to eat.
Its not just the teat. Have you decided how long you want to do bf? Reason being if you r going to change to fm, baby might reject like how he reject the teat now. So best to introduce some n allow the baby to know there r other taste around (note that breast milk is sweeter compared to fm, baby who r very used to breast milk might reject fm initially too. Pls do take note once the can of fm is opened, the fm can only last 1 month. FYI) I give My baby 1 feed of fm everyday or every 2 days. just in time the can of milk will finish by 1 month. You can ask your friends for some milk powder too n see if your baby is ok with the taste of the fm before you purchase any cos it's expensive!