Why my device is not booting up

I have Sony D6653, It was working well. I was chatting on messenger and downloading an app from google play, Suddenly my phone froozes and sometimes later it automatically show Sony logo and wait for 2 seconds and turns off automatically. Now when I try to power it just vibrate one time and show Sony logo and restart and again same thing. When I pluge in the charger, the red led glows and again same thing. Now please tell me what should i do. Plzzzzzzzzzzzzzzzz