unusual bleeding

Hello I'd like some help please, today I experienced bleeding for about an hour, firstly I had a large about of creamy cm then bleeding half hour later. It was bright red but very thin without clots. ( Fresh)no cramp or any sign it was coming so it took me by surprise as I'm on day 17 of my cycle.  We're currently TTC and believe I ovulated a couple of days ago but test were negative so can't be sure. I'm due AF in 12 days. This cannot be ovulation or implantation bleeding can it?