The booking status tells you what stage the booking is currently in. A booking can move through several different statuses.
The booking has been created and is waiting on the Pro to accept or reject it.
The Pro has accepted the booking and it is now considered "scheduled".
The Pro has rejected the booking, likely because the Pro:
Has availability conflicts with the time you selected
Already has accepted a large number of other bookings for the day you selected
Either the Pro or the Customer has canceled the booking. If a cancellation reason was provided, it will be viewable in the booking history tab of the mobile app.
The service has been completed.
Doable has refunded the booking charges. This could mean either part of the charges were refunded, or all of them.