Pumping

Michaela • Breast feeding mommy to a beautiful little girl ! Kinslee Marie ❤️
I was getting 4 oz out of each breast pumping 3-5 hours. My milk has been decreasing to 2-3 oz every 3-4 hours and today I pumped every 3 hours on the three hours sometimes 20 minutes earlier and only pumped 1 oz each !  What is happening! And how do I stop it?