Recently I Had Bleeding For A Few Hours And Thought

Recently I had bleeding for a few hours and thought I was getting my period, only to find hours later that I was no longer bleeding. I haven't had unprotected sex (or sex period) but it's been 9 days since the bleeding occurred and I began to wonder why this happened. When I Googled it the only answer that came up was implantation bleeding. Concerned, I searched "can you get pregnant without having sex" and was shocked at the results. I don't believe any semen or fluids were near that area at all, but if I was somehow unaware and they were transferred by hand somehow, would I have a chance of getting pregnant? If so, how high? 8 days after the bleeding occurred I took two early result tests (first response) and they said I was not pregnant, but since this has never happened before I am still a little paranoid. I was wondering if you guys had any insight as to what may be going on.