Am I running out of breast milk?

Shelle • 29-NJ- two boys,three girls-blended family- 1MC 🌈👶🏾🎀 7/1/18

This is the 2nd time I pumped today and I wasn’t able to make more than a 4 oz bottle. Normally I can make 8 oz bottle in one pump session. Where did all my milk go???