Xperia Z2 :: Videos Don't Rotate When Phone Is Held Horizontally

After the 5.1 update, i noticed that videos don't rotate when the phone is held horizontally. also i made a video call and when i rotated the phone the screen became unresponsive and kept going on and off unless when i held the phone in a certain angle which i cant figure out, i dont know if this issue has been there the whole time because the first video call i made on the phone (via skype) was after the update. also when i unlock the screen sometimes the colors fade and become lighter, and the screen itself freezes for 2 seconds.