new born will drink milk every 1.5 - 3 hours depending on the baby. You need to have patience. don't force your babye if he/she is not drinking all 3.5 oz. otherwise, your bb will just throw up (throwing up is not good for baby and if he/she is used to it, it will damage the health). Just feed whenever your baby cry.
Don't give up and don't worry, most baby are like that. your friend may only tell you the good side of their own babies. give your baby a few more weeks, when the stomach is more mature, it will be much better.