how can I keep my milk supply for Breast feeding well working

I start a new job in the new year. I'll be working 5 hour shifts till February than I'll be working 8 hour shifts and I can't pump at work. I work at a juicing place so it's 8 hours straight with 5 minute breaks and it takes me half an hour to pump so no where near time to pump. How can I keep my milk supply we'll returning to work? I also am Breast feeding constantly when I'm not going to be working and I Breast feed every 3-4 hours right now sometimes when she sleeps through the night I go an 6-8 hour stretch without Breast feeding but resume when she wakes up like nothing happen.  I pump between feedings right now so I can store enough milk for her to have well I'm away at work. But I don't know how to increase my milk supply and keep it going when I'm working 8 hour shifts she will only be 2 months and a few weeks when I start working 8 hour shifts? Advice on how to increase milk supply? And keep amilk supply well working 8 hour shifts that I can't pump on.