supply and pumping

My lo is 10 weeks old and I EBB. I have been pumping once a day to build up a back-up supply. For about 6 weeks I was pumping mid-morning after the first feeding. I was getting anywhere from 6-10 ounces! A few days ago, I switched from pumping in the am to pumping before bed due to the fact that I will be going back to work and won'be able to pump extra in the mid-morning anymore. Now that I'm pumping before bed, I am hardly getting anything! Any insights? Will my supply increase if I keep pumping before bed?