Google pixel 4 says I've used 4.3 GB in one day?

Won't let me show a picture but it's been acting weird today. I says I've used 3GB today just because of my hotspot? I only had it on for a couple of hours! It also went from 20% to 10% battery in the span of about a minute and then the battery started working mostly normally. I'll try turning it off and on again but also any suggestions why it did this?