Keep calm, here's what you can do.
You've sent him a booking request
The CHT (Customer Happiness Team) checks up on each booking. If a host takes too long to reply, we'll send him a little reminder.
Your booking is already confirmed.
If you haven't already, give him a call or send him a text. By going to "my trips" then "more info" on the trip in question, you'll be able to find you're hosts contact information.