Implantation Questions!!

Hi, can anyone help me with this please?! I'm 14 or 15 dpo and have been having ewcm (sorry tmi!) tinged with brownish blood on and off for the last day and a half. Could this possibly be implantation?? I have pcos, but i don't think this is enough for af - only light like spotting. I know it's a little late for implantation, but how long does it take for the bleeding to happen after the implantation itself? I have never experienced ewcm or spotting before a period so I find this really strange. Last hpt was a bfn with frer two days ago. I am planning to call my doc, but would like to know if anyone has had any experience with this! Is there any possibility I'm pregnant?? Should I test again? Thank you so much!!