Periods after nexplanon!

I've had my implant out for nearly 3 weeks now and there is no signs AF is on her way any time soon! I've been tracking with OPKs and got a positive last Sunday - so everything's clearly woken up! I'm just wondering if/when should I expect AF? keeping in mind me and my OH have been having unprotected sex since I had it removed right until the day I ovulated so there's a chance I could be pregnant? (negative hpts so far though) any advice please as I'm getting quite frustrated!