is my baby's underweight/normal/overweight?

So my son was born weighing 4.8 lbs (less than 3rd percentile) at 36 weeks. He was a tiny baby. I didn't have enough milk supply (and latching issues) so I had to supplement almost from the beginning. So he's been on formula and breast milk both. He luckily had a good catch up with his weight and now weighs 14.9 lbs at 16 weeks. However few days ago I took him for a check up and the dr said he's going near overweight and needs to be controlled and I shouldn't give him milk before 4 hours. I was confused. He already takes less milk and I'm concerned about dehydration. What do you all think? Is he near overweight?