Don't know what to think?

So to start off I'm 8dpo and AF is due on the 18th. Sunday (6dpo) night I went to the toilet and when I wiped I had a small amount of light pink blood on the tissue. First thought was implantation bleeding, so straight away I told my SO and did some research on it, it sounds like it could be implantation. Tonight I'm having slight cramps in the middle and one side of the bottom of my tummy (where I normally get ovulation cramps) I know I'm not ovulating. I was wondering if this has happened to anyone and what was the outcome? Or what do people surgest, thank you for your time x