This wait is killing mee.

My SO & I had unprotected sex the 29th, I'm now 15 DPO.. I've had so many symptoms, decided to take a test on the 12th, sadly it was a BFN...but, I'm 2 days late on AF.. no signs she's even coming. Seems like my breasts are only getting more sore as the days go by. When should I test again? And how many of you guys got your BFP 15dpo or later? I'm trying to hard to keep my hopes up.