I'm here again! Tell me, who knows, in the maternity ward I was giving…

I'm here again! Tell me, who knows, in the maternity ward I was giving someone else's baby breast milk because she was hungry and her mother didn't have any, and my daughter was always sleeping and eating little... so they say if you feed another child, the milk will disappear or become less, the mother-in-law said that. Now, it seems like I have little milk ?