Last month I spotted pink mucus Mon. & Thur. then had a period the following week. My periods are a 28 day cycle usually lasting 6-7 days. It only lasted 3 1/2 days. This month the same thing happened. Could it be implantation bleeding or could I be starting menopause? I'm in my mid 40's.

For it to happen two months in a row, it quite likely could be perimenopause, the start of menopause. For some women this can last several years with periods fluctuating between normal and irregular.

Although not the norm in mid forties, pregnancy can still be a possibility. Some women do have some spotting, or even bleeding, in early pregnancy.

I'd set an appointment with your gynecologist. They will of course do a pregnancy test, but also discuss the possibility of perimenopause or other possible reasons.