No worries! Be sure to first check your deleted items or trash folder in your email (I'm sure you already did!). You can call the helpful agents at the toll-free reservations number, 1-800-435-9792 (1-800-IFLYSWA) and they can send you another email. If you don't have the confirmation (PNR-passenger name reference) number handy, be sure to have the form of payment within reach because they will likely ask you to confirm the form of payment used.
It is almost 2 decades spent in the Airline Industry as customer contact employee at different levels. And still on... I am now a Flight Attendant but I still like to answer those pre-flight questions of the passengers :)