Battery and data usage gone wild

[Idofr]

Hey everyone,

I have no idea why, but for the last week or 2 the phone runs of out battery much faster than it used to, on top of that although the month started yesterday, i've received a message from O2 today saying that i've already used 50mb!! I've checked the background apps, and there're only "Amazing weather hd" and "battery sense" runing in the background, neither not a well known battery killer.
Gps, Wifi and etc off (everything except for mobile data, restricted to 3G), also i've not been using more Facebook messaging, Whatsapp or emails, so this should act rather normal.
Does anyone have an idea what can it be, or how can i trace my data (since Nokia are too kind to share their Data Sense with the rest of the world)

Thanks

 

[hopmedic]

This is where I'd look into Data Sense, and see what's using the data, but since you're on O2, I'm guessing that you don't have Data Sense yet, correct?