Okay weird "butterfly" feeling in lower abdomen

Okay so I have been tracking my bbt for months now, so after I ovulate my temp goes up after ovulation and drops 2 days before my period. This month it dropped at 6 dpo and keeps dropping lower and lower! I'm waiting on my period now because it looks like I'm out for this month but I have been getting this weird "butterfly" feeling in my lower abdomen and some light cramping. Could implantation happen after a 4 day temp drop? I'm so confused