My internet usage is very very high?

I have been on the internet as per usual and my usage has sky rocketed!
I usually use about 50- 80 GB just on this one PC but in One Day, I used 1.3 TB.
I did nothing different on this date and I'm really really confused.
The things I do normally:
Host a game/web server (10 people)
Play lots of minecraft multiplayer
Watch a lot of youtube videos
Check emails

Could anyone tell me what's using it so much?

Thats about it!
P.S I run a program called NetWorkX and this tells me my usage!

Maybe you keep seeding torrents? Maybe your neighbours steal your Wi-Fi!

Is your wi-fi secure? Some one else is bleeding you…

Somebody is using you Wi-Fi network Put password if you don't have it.Change network password if network has it