Internet usage is being drained when i'm not doing anything?

Alright so i recently got a new computer, A lenovo. It has McAfee Antivirus and is windows 8.1. I've noticed when i start it up the data usage goes up rapidly (I don't even have it to where it connects to the internet automatically) Itll be at 90mb in like last 6 min. Ill reset it and it won't go up. Then i go and open a browser and am just surfing the web casually (no videos or images) after awhile i check again; BAM 160mb used in the last 17 min. What? I have a 15gb cap and am a gamer so this is NOT okay. No games are running. Nothing but my google chrome. No ads, due to adblock. Any solutions? I've looked in the task manager and see nothing suspicious, though i don't know what i should be looking for… Please help i don't know how to fix this!

Maybe somebody has hacked your Wi-Fi connection.
Try uninstalling mcafee and get malwarebytes/Kaspersky(if you have a credit/debit card), that may also fix the problem.
Try downgrading to Windows 7 by either pirating it from kickass.to or buying it legally.
If you pirate, you will need tixati.
And check if any auto-updaters are on by going to services.
Search services in windows search.
You can also try to install Advanced System Care to deal with some of your issues IE viruses or what's making your computer slow.

I use around 60 GB a month. I listen music and watch videos and all other pointless stuff that most people do on their computers. I do not think I use internet a lot so I believe 15 is the bottom of the bottom cheapest internet connection that there's good only for checking email and living in fear month after month that you will have to pay extra

I helped someone with exactly the same problem last week. The problem was skype(and 5 unwanted programs) which was used 700-800mb/day, even when he do nothing. After uninstalled, barely 200-250mb/day. This program is installed stock in windows 8.1. As soon i finish to format my laptop, i uninstall this ****.

But, sometimes somes websites can eat a lot of data with a ton of ads in their web page, even if some are hidden.

So, uninstall skype and unwanted programs. Should be fine after

Windows 8.1 + McAfee is about that size. Sounds about right to me.

Install Wireshark and let it monitor your connection.
Try using msconfig to turn off all startup applications and load them one at a time and check data usage with each one to see which ones might be moving data. Turn off any torrent software or file sharing software.