Hello, I Took The Afterpill On Day 29 June 36

Hello, i took the afterpill on day 29 june 36 hrs after having a problem with the condom because it broke after a few minutes. on July 4th i had some brown bleeding and alot of cramps like i have when im on my period. This lasted 4 days because of the ECP. My normal period was supposed to start 19 of july and so I took a clearblue digital test and it was negative. 24 of july i made the same test and again it was negative. My question is when does my cycle really starts? Should I start counting after the bleeding I had days after taking the ECP or should i stick with the normal date that was the 19 of july? my period hasn't come and I'm worried im 18 years old.

thankyou very much for your time