What's going on with my cellular data?

I have an iPhone 4 with the 3GB data plan. I keep getting messages saying that I'm using a lot of my data and that it's charging $10 since I went over and giving me an additional 1 GB. I know there's something wrong because I was getting these messages at like 11:31 p.m. (All at once) and this was when I was sleeping! The first message said that I've used 65% of my data, then it said that I used 90% then it said that I used over 100%of my data and that their going to charge $10 for an additional GB! Again, this was all at once at 11:31 p.m. Which is weird because if I were to use that data it would've taken me forever and I would also think that they would send me a message way before hand that I was at 65% of my data. That's what they did before. Oh and another indicator that something's up is that so once I got these messages, I turned off my data and then, I got another message at 1:08 am saying that I have used 75% (768 MB) of my additional 1GB. Which is crazy because again, one I was asleep, two that would not have used that much amount of data in a couple of minutes, and three I turned it off.

I also looked at my cellular network data and it says that I have "sent" 616 MB and "received" 10GB! I did some research with similar cases that said they "sent" 4GB and "received" 4GB and people were freaking out. I would like to know what this means and what I should do.

This has never happened before and and please be kind.

It is hard to tell what is going on with your Iphone. Try to turn off all apps and data for now and call your carrier As soon as possible to explain them your problem before they will continue to charge you like crazy.

Obviously you need to call your carrier, a messageboard won't know