From personal experience, the long wait for an answer is normal. Notifications differ from opportunity to opportunity. Sometimes they take a few days, sometimes they take a few months.
If you don't get the position, you will be receiving an e-mail telling you so. (It goes without saying that you should check your spam folder for mis-routed messages.) With the volume of job candidates that Southwest handles, I'm sure that some candidates may be occasionally overlooked. If you don't hear something soon, you may try reaching out to the recruiter you interviewed with.
Don't give up yet!
