Today, I was listening some music and suddenly my phone rebooted. When it booted back, it rebooted again after it notifies "Loading Internal storage". So the problem probably lies in the internal storage, I don't have an external SD card and I need to somehow do a factory reset. Apparently, I am not able to do a factory reset through the phone since it reboots in 5 seconds. I just want to keep my contacts and messages and do a factory reset. By the way the phone is rooted but it doesn't have any stock or external recovery tool :(
If you are unable to boot the internal memory and don't have special equipment you are likely going to have to bite the bullet and lose your contacts. I would re-flash the phone in this situation. Hopefully you have been using Android's built in contacts backup.