Start your game all over. You know you're in a truck, right? Get out and go to your house. You mom will ask you to set the clock. Once you do, go downstairs and watch tv with your mom. You will miss your dad on tv. Next, walk outside and talk to people a billion times. You have to stay in Littleroot Town. One person will say: Myuuuu! You will battle Mew. Though, you have no Pokemon because you stayed in Littleroot. Mew will kill you. It should be in your PokeDex once you obtained it from Prof. Birch. Go to Mew and go to Area. You will see where Mew is. Go there and you might just find what you are looking for.