Confused

Kirsty
Hi everyone. I'm just a little confused. I ovulated on 25th April and am due AF on Sunday tomorrow. 
​However on thurs night when went to toilet I had a pinky discharge put on a pad as thought oh well AF is making her debut. However woke up fri to some brown blood like you get at end of period but only when I wiped and this only appeared sometimes thru out the day. This morning when I wiped there was again sum pink. 
​Does everyone think this is AF or a late implantation.??