Spotting?

I have light pink spotting and I’m on the pill. I have one week before my expected period and it’s never happened before, I have always had regular periods but I have never spotted a week early! I know the only way to find out if I’m pregnant is be patient and wait for a missed period but I have been overly dizzy and a little crampy. Had anyone experienced this and what was the outcome? Thanks in advance for any help.