Too much milk

I have had four children. My latest is a month old now. I just found that every single time my boobs think I have like an army full of children to feed. The whole time I leak milk. This is always a problem when I go back to work. I found with my third baby I actually couldn't breastfeed for as long as I wanted. Just so when I went back to work my boobs were empty and weren't sore and leaking. Does anybody else have this problem?