I'm 47 and have always had regular periods. However, in December, I didn't have a proper period, but I did have about three weeks of spotting. It always felt like it was about to start, but didn't.
Right now (end of January) I have cramps and lower back ache, it feels like a normal period, but there's absolutely no blood.
I'm definitely not pregnant, and I haven't been under stress or done anything unusual recently.