IB OR AF ??? Help!

I'm 5 days late according to the app (& yes ttc) however as of tonight I had light pink blood.. Could it be implantation bleeding? 
Symptoms just really tired and cravings back hurts but usual as if AF was coming 
The one thing that has me driving me nuts it's that I really get bad cramps every time I get my period this time I felt light cramps.. Could I be pregnant ?