astromandi, I am afraid I have to agree with astrofan ... and given that it's been a week since April 15th, chances are JHU, as well as other schools, are done with making offers or have at least informed those on their waiting list who have a chance of getting an offer.
Still, my advice is to email several professors at the department. See on their website if it says who is the head of grad admissions committee, head of grad studies or chairman of the department and send them an email inquiring about the status of your application and if it's still being considered i.e. if you are on their waiting lists and they are still making offers.
By saying this, I assume that you have tried to get in touch with them via the generic email they leave for contact, which only connects you to administrative staff and they often have the habit of not replying back and/or being too lazy to make an inquiry on your behalf.
This being said, if you don't get in anywhere, this won't be the end of the world, quite the opposite actually - you will have some time to prep more for your tests and score better, hopefully get some extra research experience/publication under your belt and rethink your school choices and approach to a successful app now that you have a better idea what may be the strong and what the weak points in your profile.
Best of luck