Is this a period cd16?

As the title says could this be a period midcycle? I came on my usual period on January 10th but this only lasted 3 days which is odd for me as usually it lasts around 5 days. It wasn't very heavy it was enough to change my sanitary towel twice a day. Now yesturday I was on cd16 and I started with light pink bleeding so I popped on a sanitary towel and it continked light pink , not much but enough to mark the pad. But when I wipe it seems alot darker and a bit heavier. I have also got a few niggling cramps but nothing major, today is the same not much in the pad but darker when I wipe. I still have 2 weeks until my usual period would be due. Does anyone know what this could be? Me and dh only had sex on cycle days 5 12 and 13 so I doubt it's implantation.  Thanks