Went to fly tonight and it was m first time since switching over to NAZA mode. Everything was checked before takeoff. S1 and S2 switches up, had 10 - 12 satellites. antennae at 90 degrees. Everything the same as always and like when I was flying in Phantom mode. Shortly after lift off and while doing maneuvers at about 20 feet up and about 100 feet away, she started to drift all over the place when hovering. Then she started moving on her own with no input from me with the sticks! The controls were working but a couple of times I had to fight her to make her go the direction I wanted. It was really scary! In my haste to get her back on the ground I had a minor crash with her landing a little hard and blades tipping into the grass. That was the first time I've ever had that happen and always land on the ground. I think if she had been very high up or far away from me, I would have lost her tonight. Does anyone have any ideas on what might have gone wrong or what may have happened? Should I switch back to Phantom mode...can I do that?