Af/breakthrough bleeding/implantation??

Nathie
Hi! I have a regular 26 day cycle, and for the last week my breasts have been incredibly sore which they never are. Then suddenly on cd 23 in the evening i started spotting, followed by cramping and started bleeding. I was sure this was Af and didnt think twice about it. But now it's cd 25 and it stopped.... No bleeding no cramping. And i usually have heavy bleeding day 2-3 and its always 5 days... Not 1-2 with moderate bleeding for a day... 
What do u think? Has anyone had this? Af? Breakthrough bleeding? Implantation bleeding? Just a weird cycle?