dropped a rank after not playing for under a week>?

do you let anybody play on your account? becasue you only drop ranks in plat and higher if you dont play ranked.

I might be wrong, but I believe if you under plat it wont let you drop tears, say from S5 to B1 but you can drop rank, say from S4 to S5.

however to drop that far in less than a week, seems fishy for sure