Which program? I had an interview with RISD at the beginning of the month and started to get a bit nervous after not hearing back for 4 weeks, especially after hearing other programs like GD and I believe Painting had received informal acceptances weeks ago.
I sent an email to the head of the department yesterday to follow up on the status of my application, and they replied with an informal acceptance, saying the official notice with financial information will be going out on Friday. I therefore suspect they weren't necessarily planning on sending out informal acceptances, and I would have otherwise found out upon receiving the official notice through the portal had I not inquired. It seems like each program has very individual application timelines and methods of contacting successful applicants.
Have you heard of other applicants in the program you applied to receiving any news? If not, I would reassure you that no news doesn't necessarily mean a rejection at this point.