Two possibilities that I can think of. The first possibility is a thermal that moved horizontally because it could not punch upwards where it originated, but found a weak spot in the "roof" over the field where you were flying and moved briskly upwards.
The second possibility is two winds moving towards each other from opposite directions and going vertical where you were. When either of these occur, there will be no appreciable wind at ground level to as high as maybe hundreds of feet. Even though it's moving up there, at the ground it's a stalemate with no movement.
There is also this thing called a seiche, which generally applies to bodies of water rising at one end and dropping at the other, the vertical displacement being caused by inequalities in atmospheric pressure. If this is combined with either or both of the above conditions it will make the air move in truly mysterious ways.
Either that, or you've got to cut back on what you're smoking.