Not all of the congressional offers have been made - a bunch of them were though. Some candidates that are likely to win are not 3Q yet. Of those, some may not be (medical is a big hold up for many candidates) and the next candidate that is 3Q is still waiting.
What to expect next if you are a 3Q with a nomination from a MOC: some of you will get an offer for one of the national spots likely within the next week or so. If you are in a competitive district/state, this could be your future. You may not have won the district, but are highly competitive. This is the next "wave".
Some candidates could end up with the second offer if the first candidate declines or are further down in the national standing. Since the offers have a 45 day required response, that should happen sometime before mid April. These will be on a district by district basis so don't expect a "wave", but rather a weekly push after admissions meets. In the past, these were usually done/sent on Tuesdays and arriving on Friday/Saturdays. Of course, if you are in south Texas, it could take a bit longer than say New Jersey.
The last wave will be USMAPS. There are usually about 200 of them that gain admission in the late spring. So with the 500ish offers that went out last week, plus the others earlier in the year, there are somewhere less than 400 spots left in the class. 100 are for presidential candidates, maybe 100 for unresolved congressional vacancies, ROTC, and sons/daughters of disabled vets. That leaves about 200 for national spots.
Unfortunately, there are always 3Q candidates that are not selected. Around 50% by last years numbers. Many of them went off to college and are among those who have been offered this year. So much can happen between now and R-Day. Offers go out all the way till the end, so stay ready.
Contact your FFR if you have questions. If they can't answer them, I'm sure they'll refer you to your RC.