i Cloud upload

I just switched from iPhone 12pro with 128 storage to iPhone 12 pro with 256 of storage. The only reason I switched was because my original phone was lost and they did not have another 128 available. I had plenty of extra storage in cloud before the switch. I am now receiving an alert that I do not have enough I cloud storage for the new phone....i have not added any new apps etc, so why would my I cloud storage now be maxed out?