Check the website where you check your application status on. It will update the status faster if you are dinged. I was in the same boat as you, I interviewed in mid Feb and didn't hear anything from them in mid March. One day I checked the application status website and it said I had been denied. A couple weeks later I got a letter in the mail from them stating the same thing. Good luck to you, hopefully it's not the same case as me but it sounds like it.
I recall your posting back in mid march about checking that website, so as OCD as I am, I probably have been checking that 8x a day since then.
I always assume the worst...