Data Meter shows 1.2TBs of usage over 5 days?????

I had my internet installed this past Saturday (Aug 1, 6 days ago) and over the next two days, had pretty average values for usage. Then on Tuesday, my data SPIKED to ~600GB over one day. Then 300GB and 200GB respectively on Wednesday and Thursday. How is that possible? To give context, I'm a student whose classes started on Tuesday. I've downloaded around 800MB of books, PPTs, and PDFs over the past few days. I've listened to maybe 3hrs of low-def lecture via Zoom each day with around 2hrs/day of YouTube (so 6hrs the past 3 days). There HAS TO BE A HUGE DISCREPANCY SOMEWHERE. Hundreds of GB of usage is absurd.