Hi, I am using this LG optimus L3 E405.

Every night before sleeping i would turn off the phone and switch on the phone the next morning as usual. But today when i swtiched on my phone, it is like it has been formatted. It asks for the date/time etc setting bla bla bla. Then all my contacts, apps, message, contact logs are gone. it is like a new phone. Why is this happening? I just switched off my phone as usual and didnt take out battery or anything.