Samsung Flight II Problem

I bought this phone 2 months ago, and suddenly I am not able to read texts I receive.  When I attempt to read, the ATT WorldPhone screen comes up and eventually I see my usual screen again (my phone appears to be re-booting).  If I then try to view text messages, it is marked as read so I cannot view it.

When I choose Messages from the menu, it pulls the icon onto the desktop and will only let me create a message. If I go Back, then the phone re-boots again and I get the main screen.

This is very frustrating!