There is often confusion who is ruling during each chapter of Daniel. This arises when readers do no understand the special structure of the book. It is not in chronological order - but rather Chapter 2 and 7 mirror each other (from different view points) or fit together, 3 and 6 fit together each as as does, 4 and 5 in what is called a chiasm. The final chapters are a series of specific prophecies.
 Reproduced from Andy Wood's sermon: Sugar Land Bible Church, Sermon Series "Daniel" 2017 (accessed 13 May 2017) - slbc.org