I could have written this verbatim! I came out of the staff into the manager position in my first manager position and I thought that was what made it so hard and why people suddenly seemed to hate me. Now I am in a position where I am new to the organization and it is no different! It is the position they really hate. I have found when you talk to staff one on one, they realize many of the things you mentioned and almost always say they would never want the job, but most of them don't realize that they are part of what makes the job so difficult. Being a unit manager is one of the hardest jobs there is. You are squeezed from both sides. Try to not take things personally. Make time for you. The work will be there the next day. Hold people accountable for following rules and treat everyone equally. Do your best and realize you were chosen for this, so there are people who thought you were "the best"!