Implantation bleeding?

[NRosezella]

My last period was December 23rd. It was heavy but only lasted a few days. My boyfriend and I had sex January 2nd and I was pretty sure nothing went inside of me. However, on January 11th I began bleeding dark brown blood and it is still happening. It is enough that I need to wear a pad throughout the day to prevent my underwear from staining, but it is no where near as heavy as my usual period. Could this be implantation bleeding or just AF? I feel like it is too soon to take a test.

 

[MoonKitty]

Sounds like it could be implantation if you don't normally have break through spotting/bleeding.