Implantation bleeding

Bonnie • Mommy of 2 handsome boys. Married to the love of my life with baby #3 on his or her way! Jesus’ girl ❤️

So I started spotting today... very light pinkish. My period is not due until the 21st. Implantation bleeding or just count this month out? I never had implantation bleeding with prior pregnancies but then again I never even heard of it until I came on this app! Has anybody ever had it.. and how do I know the difference?