Yes, honey, you're textbook. A period can come out of nowhere as the body adjusts to varying (reduced) hormone levels associated with the onset of menopause. You could talk to your doc about hormone therapy if you're really uncomfortable with hot flashes.
Hi,
Yes, it is quite possible at 54 years old, and is usually occurs in the 42 - 58 year old range. It can officially declared after one year of not having your period, with many signs leading up to that such as the lack of sleep, hot flashes, etc. It's probably best to see a doctor at this point if you can. Good luck to you :)