Implantation vs menstruation - TMI potential.

Help... What distinguishes between the 2?

Implantation signs: I have had a 2 day bleed - light and started out pinkish red and stayed a brighter shade of red the whole time. This started at CD27 which is very unusual, that is also approx 10DPO but not sure exactly when O'ed this cycle. No lining or darker blood present in any discharge. Also passed mucous at the same time.
All of the above very out of the ordinary. General cycle length is around 30 days.

Either way - Temp spike and drop just prior to bleeding, temp was low for a couple of days but has risen slightly now bleeding has stopped.

Is there any clear cut answer for this scenario as I just feel a little strange this cycle and this has never happened to me before.