Can someone help me never seen this before

[TTCbaby2011]

I am 7 dpo today and my bbt temperature went way below the cover line. This is my 10 th cycle bbt charting and I have never had this before. Not a single temp below the cover line. I use tempdrop for my bbt temperature. Can someone help me with insight on this, Thank you for your input!

 

[TTCbaby2011]

Anyone?​

 

[Deethehippy]

Could be implantation drop but could be something as simple as a cold thermometer in a cold bedroom. See what tomorrow's temp does.