How tall was the tree when you moved it? How long ago did you dig it up? Summer is probably not the best time of year to move established shrubs and trees, and it is probably quite stressed. I am not sure watering it twice a day is helping either. In fact you may be killing it with kindness. Sometimes wilting leaves is a sign of overwatering. Like many kitchen aromatics, they come from a fairly dry climate. If you trod it in well so that the soil around the roots is quite firm that is probably the best you can do. I'd be inclined to leave it alone for a while and hope for the best. If all else fails, you can always buy small bay plants (15-20 cms tall) from garden centres quite cheaply, and if you plant them in a good spot they will thrive and grow. I had one I bought from the 'reduced' counter in a garden centre in a 1 litre pot. It was misshapen and sad, but it survived. I moved it when it was about 30cm high when I moved house, and when I sold that house it was 2.5 metres high!