My baby is like yours, can only take a very small amount of milk. I keep looking at the guides and feel scared because it's much less than the recommended amount. Now at 13 months she still drinks only 90ml max. The thing is some babies don't like to drink a lot at a time, but they will drink more often. Just watch diaper output which you already do and check baby's weight on the percentile chart. Don't worry too much :)