Milk supply

Is there a way to increase milk supply that you guys have found? I used to pump about 3 oz after my baby fed. Now I’m getting about 1. I am back at work teaching and only able to pump once. I got 6 oz the first time I did that, but now it’s consistently 3. Which will get her a bottle the next day, but nothing to store. My stash is going down and I’m expecting I will have to supplement two daycare bottles with formula. I drink water and body armor. I’ve ordered stuff from milky mama but was wondering if anyone has found anything that worked...and if I just wasted money on milky mama.