I am in the same situation, but in Vancouver. It looks like 221Gs are mainly given for two reasons - missing documents or Technology Alert List. From what I have read, missing documents / employment verification cases are resolved relatively quickly (3 - 10 business days), but if the VO asked you about your field of study, and your field of study could be in the alert list, resolution could take 3 to 4 weeks.
In terms of next course of action, there is nothing you can do, except be patient and sit tight.