Is it normal for the eCPM to drop dramatically after only 24-30 hours after my game’s release?

The eCPM was originally at $3.24 after 3-5 hours after I released my game. It dropped to $2 something this morning, then it drop to $1.22 around 4PM, and now it’s at $0.64; $0.64 is super low.
Would how often a particular ad is shown be a big factor?
Game was just released yesterday (8/21/17) by the way.