Nutrition Inquiry

My boy is 8 and half month old now, and he has been on breastmilk for now. I have tried normal formula milk (Friso Gold) on him when he was 6 months old because I want to stop breastfeeding and switch him on formula, but after he has taken approx. 30ml, he couldn’t take it and vomited all out including the previous feedings. I have tried him again at his age of 7 months, the same thing happened again. I took him to hospital and check results showed he is allergy. So I had to continue with breastfeeding. Now my milk production reduced and it can no longer be sufficient for him. Some friends suggested me to try lactose-free milk, so is there any advise for me?