Date

I just realized that the date on my iphone was incorrect. I went to settings and everything just like you'd normally do but, the thing is.. the m/date/yr were strange. It was January 5th 2554 BE. I don't understand why it says that and it's preventing from using Instagram/Facebook/Other Apps, It says "error" or "please change to correct date" and I tried moving the year back to today (2013) and it won't work. It messes up and brings it to December 31th 2554 BE. I'm trying to fix it and it's frustrating me : Please Help?