Implantation dip? BFP?

Anyone have a dip in bbt 9dpo and still get a BFP?
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​I am on CD28 and AF Is due in a few days (5 or 6) temps were raising and then dipped today...
​Feeling more and more pressure and pain on my left side and the most tired i have ever been.
 
​Could it be an implantation dip or just AF ?