TMI WARNING

So when I woke up from a nap on Friday I has a little brown stringy discharge. Threw out Saturday I have had the sense thing and the same amount only when I wipe and nothing on my underwear. Sometimes it is a little pink but that's it, no red and is looks more like discharge that blood. AF isn't due for 7 days so it's a little weird to have this. My partner says it could be implantation bleeding. Is this possible that I could have this weird brown and pink discharge type of stuff that has lasted for over 24 hours and it be implantation bleeding?