Hi! I am a mom of 4 ages 9,7,3,3 and have breastfed them all. I am also a breastfeeding counselor. Your baby is doing fine. Babies are just fine to be exclusively breastfed up to 6 months before introducing solids, but you can introduce them earlier, if you like. Mine were about 5 months when we introduced solids. Breastfeeding is actually easier than bottlefeeding when it comes to knowing how much to give your baby - you just look at the baby! If they are having a good weight gain, good diaper output and are happy and satisifed after a nursing, then they are getting plenty to eat. It is always important to follow the baby's feeding cues, regardless of how you feed them. It is important to not overfeed, which can be done when bottlefeeding, but not when nursing. When nursing, the baby will be happy and come off the breast when done, and we don't push them back on the breast. But with a bottle, sometimes we have a tendency to encourage them to finish a bottle when they are really already full. Just always remember to follow his feeding cues, and he'll be fine. You are doing a great job - breastmilk is his perfect nutrition!!