Losing my supply??

Hi ladies.

I recently went back to work 3 days a week.

My LO is 11mo and we EBF. I have not gotten my period back.

For the first few weeks I have had no problem pumping to replace what he eats while I'm gone.

Today and yesterday I hardly have anything come out when I pump. Where I would normally pump 3oz per breast, I am only getting barely 1oz per breast.

Any ideas on what this could be or what I can do?

I'm drinking 100-120oz of water a day, eating oatmeal for breakfast and I'm in a relaxing place when I pump.