Hey Judy, sorry to hear you've not been able to get in. The time it takes to login maybe longer than usual. But if black screen has been present for over 5 minutes, I would close the session, check your remote sessions in the control panel and if present remove. Then try and log in, if still unable to log in, I'd run through these or call tech support for one to one assistance.
(I got in, in 2 mins from clicking Login to having homepage present)