Wife's milk supply dropped after going back to work

So my wife just went back to work after 4 months and her supply tanked almost immediately. We're down to maybe 60% of what we were getting before. The pediatrician said it's normal but we're looking at supplementing with formula now. Has anyone dealt with this? We want to keep breastfeeding but also don't want to stress her out about pumping every 2 hours at her desk. Any tips on how to handle the transition without making her feel like she's failing?