How soon after implantation can you take a test?

Normally I would know exactly when to test, but my cycle is playing games on me...My last period was on June 12th, if I have a normal cycle ovulation would range from 6/26-6/28...however, I had unprotected sex on the 20th day after my period ended so stupid me thought I should be ok...but anyways had blood tinged mucus today, I am assuming it might be implantation bleeding, but idk, just in case it is when could I test and get an answer I could be mostly sure of? And if it is what would my due date be since if I am pregnant, I didnt ovulate during the assumed correct time?