In such a situation, Safe Mode can be really handy. The way this works is that your phone boots up with minimum features and only those features are loaded that are necessary to use the phone.
How to turn your phone in safe mode -:
1) Simply long press Power key
2) Now long press on "Power off"
3) Now you Will see a Popup to "Reboot to safe mode" Choose "Yes"
4) That's it you are now in safe mode .
How to Turn off safe mode -:
1) Simply again long press on power key
2) Now click on "Power off"
3) Now on it again after 30 sec
4) That's it, you are now in normal mode..