interview today

I got my GC approved today after interview in local office. The officer didn't stampe on my passport, just told me that I will received the card within 2 weeks. My question is, what is the next step after the approval action? Will the local office tansfer my file back to service center? Will my online message updaed as approval message? I am a little bit nervious about the verb approval from the officer(afraid he changes his mind), I guess the nervious if from such a long waiting process. Anybody here know anything about this procedure, please share your information. Thanks!