First, Congratulations!! Yes, that is indeed SUPER fast. Normally applications involving Americans go to Ottawa but since you don't have a letter, I can't really say whether it went there or stayed in Mississauga. But I will say there have been all kinds of anomalies in terms of who gets processed first for PR - it definitely doesn't seem to be done in order of application date, etc, and there were a bunch of people that got approved who applied in 2015 while plenty from late 2014 were (and still are) waiting. But since you know you have SA from the call centre, I'd just count your blessings and go from there!