Blackberry World Edition Hourglass - deleted messages

I have the BB World Edition that receives my work emails. Every so often the red light will come on (like I have a message) but instead of blinking it stay on for a bit longer then it's almost like the BB freezes. I get an hour glass that goes for 5 mins or so and then once I can get my email to come back up it has erased all of the emails from the day... I dont know what I do to cause this. :confused: Today I just set it down and this happend. I had not hit any buttons. My free file is showing 15085518 bytes. Any help would be greatly appreciated.
Thank you!!