Increase milk supply after almost drying up

Hi mummies! Unfortunately I went back to work two months ago. And unfortunately after I went back, my supply dwindled like crazy. My routine was that I would pump at work once during lunch at 1pm, and then once I got home by like 6pm my baby would latch on. But after a while, work got so busy and I had missed my lunch pump. I thought by baby latching it would continue to stimulate it, but it wasn't enough as my supply continued to decrease. Today I tried pumping but only managed to express like, 20ml for both sides :((( Any mummies had been in my position but managed to successfully increase your supply? Any tips on how I can continue to pump during a busy day at work (I work in a preschool setting)? And what would be a good pumping schedule I can follow daily? Food-wise I know probably would go back to taking 100plus and legendary milk pills religiously, but any other food tips? Any sharing would be good. Thanks so much mummies!