shaking

Hi, I am quite new here, so please, don't judge me. Ok, my problems with a drone. Everything work perfect, exept: 1: I installed gimbal, when I tried to shake drone in hand it was working fine. But when I made first flight, gimbal stopped working. Camera falls on one side and doesn't want to...

If anyone can help me figure out why at times the video is vibration or a wobble look to it. At times when I can fly out of the this. Is the motors going out ? I have balanced my blades and made sure no cables in the drone is touching the gimbal motor. I have uploaded a video to show my issues.