I feel a bit silly for asking but it is driving me nuts...?

Hey moms...question from another (very hopeful) mom here. I have had very regular period for a long time now, they come on the 19th or 20th like clockwork. My period was due 2-3 days ago, and a little over a week ago I experienced some light pink spotting when I wiped. The issue is, my husband has never d inside of me....so my question is could I have possibly gotten pregnant off of pre? I have a 5 yr old daughter, and I have been scrambling my brain trying to remember signs or symptoms or anything to clear my head. Has anyone experienced this? Thanks for easing my mind here ladies :)