Hello question!!

Has anyone had implantation bleeding?? I know everyone says it’s not common but Saturday I took a pregnancy test in the morning and it came back negative I took the test it was 9DPO because my friends asked me to go to ride roller coasters. So I wanted to make sure i wasn’t pregnant before I said yes. Well we got off a ride and I went and wiped and I had a little tiny bit of blood. Pinkish. And it was ONLY that one time. Now it’s 4 days later period due to start today and nothing (fingers crossed it stays that way) so I am just curious if anyone thinks it could of been implantation??