C.O.
L.:
First things first - take a deep breath...stress does a lot of things to your body and will affect your milk supply...I know from experience it's easier said than done...but take a deep breath..
Your body went through a big change today - you went back to work and I'm sure there was nervousness about leaving the baby, returning to work and all...
When you nurse when you get home this evening, pump again...even after nursing...then pump again before you go to bed and after you nurse in the AM.....
Hope this helps!!