NOTE: If these are all you tried (if not all then some), I would wonder if it is actually in "Safe Mode" or if there is malware or a virus on the device. If that is the case, the last option may be your best one, however you would really need to try and get your personal info off the device first, otherwise you would lose it all.
To get out of Safe Mode, please try the following.
1. Touch and Hold the "Power" key.
2. Tap "Power Off".
3. Once the phone is off, Touch and Hold the "Power" key again to restart.
The phone should now be out of "Safe Mode".
If the "Safe Mode" is still running after you restart your phone, I would then check to make sure your "Volume Down" button is not stuck. Check to see if it has anything stuck in it...