iPhone 4 lost all Calendar and Contact info

My iPhone 4 was synched to Outlook 2011 on our iMac (OS 10.6.8), via iTunes. I have had no problems with this for over a year. Today, I tried to plug the phone into the iMac to synch it, and lost all data in the phone. The Calendar and Contact data is still in Outlook on the iMac. In iTunes, under the Info tab, the option to synch with outside data is greyed out. What happened? Help!

Paula Cullen

(509) 939-4142