What you need to do is pump more, and keep your fluids up. Make sure, of course, that you're also eating enough, and that you're eating nutritious foods.
Hydration is very important. Even if you don't feel thirsty. Thirst is 90% habit. Make sure you're drinking about 10 8-oz glasses of water a day (most should drink 8, but you're nursing, so you need even more).
Can you pump at work? Is there a private place to do that? Some women just do it in their cars at lunch. Pulling the shades down helps. I knew a women who used a bathroom stall.
Just use it to do some reading and to force yourself to have some quiet time for you.
At home, pump more, too. Have your husband do the dishes after your children go to bed, and/or pump in the mornings before everyone gets up.
You'll find your supply increasing within a few days.