Milk Stash Help

I’ve been pumping for about 8 weeks now and have been able to pump enough to feed my son and store a bag of milk each night from Dec 19th until Jan 7th. But all the sudden my LO jumped from eating 3-4oz per feeding to 5-6oz per feeding (there was a growth spurt day of a couple 7oz feedings too). On top of that my milk supply appears to have decreased a little from 6-7oz (pump both sides for 30min) to 3-4oz. I’m desperately trying to store enough milk for when I travel for a wedding come March 14th this year (will require about 40 five ounce bags), but with my LO increases appetite and my limited milk supply it seems this won’t be possible. I want to try my best to avoid the need to supplement with formula. Any advice, tips or tricks to help me out?