How to start building a milk stash/increase supply

I’m exclusively breastfeeding my almost 5 week old we’ve been doing great! I return to work in 3 weeks and I want to start building a freezer milk stash for when I return. Right now I’ve started pumping 1 hour after her morning feeding and I barely get 1oz and I’m putting those together to make 4oz baggies but it takes me 4 days to make one at the rate I’m going right now haha. Will my supply increase little by little as I keep pumping? Should I add more pumping sessions in the day? Any tips?