Be the bigger person
When someone treated you like shit; used you and deserted you. The shock and anger can be overwhelming. But you have a choice. You can be hateful, resentful, and curse them all to burn in hell. You can be pitiful and cry, or beg for a second chance. Or you can chose to elevate yourself, and be the bigger person.
There is no need to be bitter about the situation. Instead, you should seize the opportunity, and take this chance to have a fresh start. Be optimistic, stay calm, stay professional to the last minute, and by doing so you have become a better person, or even a “Saint” according to R. Friendship might not last forever, enemies certainly don’t stay permanent either.
Do what you do the best, and still care for people around you. In fact, judging from their reaction, you have handled it exceptionally well. Actually, it couldn’t have ended any better than this. Your professionalism made a lasting impression on them, soon they will realize it was such a shame to lose you.
Time for a new start!