Hi,

Many mothers express concerns about their milk supply. When our babies are fussy and unsettled we take it so personally.
You will always have enough milk for your baby - your breasts are never really empty, even when your baby is having a cluster of feeds quite close together.
For a baby, breastfeeding is not all about being hungry. When they feed they get milk, but they also get a surge of great hormones which help them relax and to sleep and to digest their food. When they are breastfeeding they are close to mum - and everyone wants their mum when they are a bit out of sorts. He could be feeding for a number of reasons, but it sounds like you are making plenty of milk. He doesn't need anything else. And it looks like the evidence is before you - he is growing and thriving.
I second the sling. It is hard work when your partner can't be close, with a baby and a toddler - you are doing a great job.