Help high data usage

[iamgroot]

Bit of a strange one for me, but over the last month my data usage has more than doubled. I have checked the data usage stats on the menu and there is nothing out of the ordinary on there in that I can see what is using up my data, it just appears that whenever I use Internet ( chrome or dolphin ) it uses disproportionate amount of data.a simple Google search,click through to a page and scroll of the page uses 10mb for example. I got a mate to do the same on his phone and it used less than half of what I did. Could it be a virus or something like that?