Why Google messenger used 4.17gb of data usage from my cellular internet?

[AC Question]

In the 15/2/17 I started a new cellular cycle, and a few moments ago I checked my internet usage and it jumped to 7gb, and the app that was on the top of the list was google messenger that came with my Nexus 5x, I am running Android 7.1.1 and in my last cellular cycle it used 4.30gb , and that is odd, because I haven't used Google messenger for a while now(I am only checking the notifications for my google 2 step verification.
Please help me,
Ofir aviel