I had a tubal ligation 11 years ago (I am 37 years old). I have never been more than a few days late. My period is now 18 days late. About 2 weeks ago I noticed my breasts were extremely tender, only slightly now. I've had frequent headaches and am cramping at times. Is it possible to be pregnant or am I possibly going through perimenopause? I would appreciate any input and advice.