@leocg The problem isn't my actions on Opera, it is that Opera is using the network constantly while idle and when I am not doing anything on Opera. If Opera uses data 24/7 600kb/s, the data adds up.

@leocg Youtube, Email, Google

I open up the opera task manager and I see "Browser" using 600kb/s network. I had to exit opera and launch it without all my tabs and it goes to 0kb/s on idle. Next day, same problem. So I end processes one by one to see if there is a culprit. "Utility: Network Service" is the culprit. Upon ending that process, it pops up again but does not instantly make the "Browser" use high network usage yet.
Please help, my internet plan is a one terabyte plan and last month I used 2 terabytes of data. Windows 10 data usage shows Opera browser transmitting 1TB the past 30 days. I really like Opera, but this is killing my data bill.