I have the same problem. My boss is a scrawny middle aged buck toothed woman who has a hatred for men and scousers. We used to be quite close when she was supervisor, I was sat on what is affectionately know as "the golden table" which is where her harem of favourites sit. She used to tell me everything, and she was always the first person I'd go to if I needed anything. She was the one who used to tell me to go for other positions in the department to better myself and always suggested if anyone was off sick or on maternity that I cover their role to stronghold my position in the office.
That all changed when the manager left and she moved into the manager role. All of a sudden I was the badboy. I was covering a colleagues job which meant staying longer and working twice as hard (I was still doing my previous role at the same time). I never got any praise or anything. During this period, another colleague and myself were asked to swap from a normal 9-5 to a 10-6 on alternate weeks. This was a hassle for me because I take my brother to work, I look after my mum and I was going to the gym for health reasons. My colleague dropped out so another had to replace him......this went on for 9 months. At the end of it, I was on holiday for a week so a colleague had to cover my shift, and they organised to split the last week between them and another person. When I got back I was basically told I was doing that shift, and when I said I wasn't, that's when we stopped communicating.
Now I don't get a hello, a bye....nothing. She's totally unapproachable. She has her harem of golden boys on her desk who can basically do whatever they like, which includes extended breaks and an hour of footy talk before any work is done in the morning. The rest of the staff are now treated like shoot, can never be more than a minute late from their break, and we're never allowed to talk.
Now things have changed and are so bad, I go out of my way to be as unhelpful as I can and make things harder for her. I've told her I don't like her, or the way she tries to run the office. My girlfriend works in HR so her and the senior management know what's going on before my boss tried to pull a fast one.
basically, she's an peanut, we all hate her, and we all wish our old boss was back!