I'm so sorry that you're so tired and stressed. Great info from the PPs. I just want to add that nursing throughout the night is helping maintain your supply. Trying to limit that will only add to any supply problems.
You could consider pumping immediately after nursing. This will signal your body that you need more milk and can help you build your supply up. You probably won't get much milk, if any, from these pumping sessions but doing this for awhile will cause milk production to increase to meet the extra demand. Can you try to add an extra pumping session or two to help retrieve more milk for daycare? Maybe on the weekend? Doing that can help stimulate extra milk production as well. I know you are already tired and these things will mean extra efforts for a little while as you body adjusts, but they can often work even better than supplements to increase milk production.
I still think that it might be helpful to try smaller bottles. Three 4 ounce bottles = two 6 ounce bottles (or even four 3 ounce bottles which is what works for me, but may be a little too much of a deviation for you). So you could send the same amount, but if he didn't need all of the bottles you would find yourself under less pressure to increase your pumping output.