LoB is not a game where you get unlimited turns and can play all day. Instead, you are encouraged to search a bit if you want to have more turns. There are several ways to get more turns. Of course, these ways only give you a slight chance of getting more turns, but it never hurts to try. There are shops, like Rukia's Kitchen, for example, where you can buy soup which will grant you one of several possibilities. There are also a few other shops and stores in LoB where you can buy something for a chance of more turns. WARNING: You could LOSE turns from using these shops- nothing is guaranteed. Just explore a bit, and you may get lucky.
The other and most obvious way to get more turns is just waiting for the new day. A new day happens three (3) times per real day, every eight (8) hours. At the new day, you will regain your full turns.