Problems with receiving calls and sending text messages on fairly new Blackjack 2 for ATT?

I got my blackjack 2 back in April or May. From day 1 it's had a case and a screen protector. The past few days it's been acting up... ever since I got home from LA... I turned my phone off for the flight and when I turned it back on it's been ridiculous. For a while, I couldn't receive calls or texts unless I turned my phone off then on again.. then I could see the missed texts and calls but how am I supposed to know to do that every so often throughout the day? Then it started just freezing when I click to open text messaging and when I try to answer phone calls. Today it didn't even show the names, just numbers, but when I'd try to answer it'd just freeze. My phone has been sending the same IMPORTANT text for the past 2 hours (no joke, it just has that little timer circle in the middle of the screen). I keep turning my phone on and off and on and off and on again and it doesn't make a difference! What is wrong with it?!?!