C172: If you weren't careful in keeping the ball in the middle and there was a certain amount of fuel in the tanks (I've no idea how much), the prolonged sideslip might have resulted in the fuel outlet from the tanks being uncovered, interrupting the fuel flow to the carburettor/fuel injection. Returning to wings level or balanced flight would solve it.
That's why you are only supposed to use the L and R selections on the C172 tanks in balanced (level) flight. BOTH for everything else.