Overbearing annoying boss

I have been working more than usual lately because my boss is sick. This is my first morning off in a week. When the alarm went off at ten till seven this morning I freaked out. I have to be to work by seven fifteen. Then it hit me like a pleasant wave. I don't have to work until afternoon today. Once I wake my kids up I can crawl back into bed for a while. I am babysitting this morning, so I can't just lay around and read like I want to. I don't mind though because at least I'm not at work. My boss is a real pain in the ass. A year and a half ago my boss moved to a new office. I was happy for her because she is a great lady and this was a promotion she deserved. I wasn't happy about her replacement. I didn't apply for her job, because I'm trying to retire without ever having had a full time job. My current boss is someone I met when I was eighteen. I have known her for years, and there is a reason I quit hanging out with her. Now she is my boss. Great.
I will describe her and everyone of you will know someone just like her. She isn't even an original pain in the ass.
She is smart, but insecure. She tries too hard to make sure everyone knows she is the smartest person in the room, which she usually isn't. If someone asks somebody else a question she jumps in with the answer, right or wrong. If something goes wrong she quickly points fingers and shifts the blame. On top of this she is a horrible gossip, even worse a two-faced gossip. When we were younger she would come over and hang out with a group of women and our babies at my house. We laughed and had fun. One day my neighbor, another one of our group, said to me. "Do you want to know what she said about you the other day." I answered "Only if you want to hear what she said about you." As I got older I realized I have some great friends, so why mess around with one who isn't that great. I put some distance between us that lasted years, until she became my boss.
Luckily we don't work together very often. I am her fill-in so I usually work alone. The other day she came in and was standing on the other side of the counter talking to me when a customer came in. I started the transaction, but hadn't got very far when she took over asking the questions. She made it clear she thought she could do a better job than I could. I bit my lips and let her go, but visualized myself jumping the counter and choking her. I am really considering changing jobs.