Mobile billing help?

Basically I'm with the mobile company EE and before my upgrade last month they rung me yesterday telling me Ive racked up a bill of over £1,000 !! I had no warning about this bill and it's direct debit so why wouldn't the money come out of my account automatically with the rest? This is all on data, I have 4GB of data and apparently I have racked up this bill in just 3 weeks not even a month which isn't even possible, I have the EE app which allows me to see when I go over and which caused me to go over, I haven't ever in my life seen a bill of over £1,000. I haven't been abroad, I don't contact anyone abroad, I'm mainly on wifi apart from when im at work which im not using my phone. I'm going to the store tomorrow. Would they be able to see everything I've googled? Because that is so embarrassing, I google some weird stuff especially when it comes to the government and illuminati etc. like would it come up exactly what I've typed in and clicked on?