SMSs deleted by phone-can i retrieve them iPhone 4

I was trying to send an MMS on my iPhone 4 from the Photos app, after i clicked send in the message window, the SMS app closed down, and my phone showed me the apple symbol for start up for a minute, then i found all my SMS messages had been deleted. Any idea what happened and how to retrieve them, or is my only option to do a restore from back-up, and i guess ill lose the messages since the last back-up.
Thanks
macbook Mac OS X (10.6.7) iPhone 4 (4.3)