how do you know if you are still producing milk?

My daughter is almost 18 months old, and nurses pretty frequently
throughout the day but sleeps all night. I no longer wake up full, and
in fact the other day went from 4pm one day to 8am the next day with
no nursing, and I didn't feel full in the morning(that wasn't
intentional, I was on the phone at bedtime and she asked dh to get her
to bed...I had no idea until he came to me without her). I can't even
tell if she is swallowing, she's so wiggly and making faces and funny
noises as she sucks. I can't squeeze any milk out. So how do you know
if you still make milk? Do you think toddlers care if the milk is
there or not?
Marie