IPhone 5 AT&T Cellular Data Issues?

Recently on my iPhone 5 with 2gb data plan with ATT, I have noticed that I'm constantly being alerted I'm exceeding my cellular data plan when I have barely used my cellular data. Last month I was alerted I exceeded my plan FOUR TIMES, when I used it how I normally use my phone, and I have rarely exceeded my plan. I'm curious as to what is going on here, because I'm being overly and I know it. I'm using my phone as I always do and I'm NEVER charged this much. According to my alerts, I have gone over my plan in a matter of 4 days! I was busy those four days and used the phone less than I normally do!

I always have my Wi-Fi on at home and my phone is always connected to it at home. I have no clue what is going, but if anyone has any idea, I would happy to know because this is becoming ridiculous. I would not be surprised if I was randomly informed I exceeded my plan a fifth time this month…

Also, between a TWO HOUR period, I apparently went from using 65% of my plan to 100% when I didn't even use it…

Added (1). I downloaded Kik, but I'm typically logged out and only use at certain times for certain people.

Did you download an app that is a data hog?