DistroKid's Musician Plus and Ultimate accounts give you access to Estimated Daily Stats from Spotify, Apple Music, iTunes, and Amazon.
Sometimes, the numbers in Daily Stats differ somewhat from the figures shown in your monthly earnings statements. They may even drop to zero on occasion. Have no fear! That's normal, usual, and nothing to be concerned about.
It's generally an issue with how the streaming services are reporting to DistroKid (API), and these types of issues generally clear up within 24 hours or so.
Also, it's important to remember that estimated stats come from a completely different system than earnings reports, and any fluctuations will have absolutely no affect on your actual earnings from streams/sales.