Working Momma and pumping

Hi! please help. Breastfeeding momma ako and I pump milk para may supply si baby kahit nasa work na ko. I came back to work yesterday, and nagppump din ako sa office. The only time I can pump is in the morning before ako pumasok that's 7am, then next pumping is 12noon then 5pm bago ako umuwi ng bahay. I work in a bank kaya medyo mahirap makahanap ng vacant time. the question is, hindi kaya humina ang supply ng milk ko? as of now nakaka 3-5 oz lang ako both breast. Any tips on how to boost and maintain milk supply if I cant follow the required timeframe for pumping? Btw, unli latch po si baby pag uwi ko ng bahay.