What distro are you using? Which deivers did you update? What hardware do you have? nvidia gou? etc. Definitely first try going into different tty with ctrl-alt-f2 or f3 etc.
it is a text based environment of you OS, you can switch between multiple text based environments. if your graphical environment is just black, but the OS is still active you should be able to switch to another text based environment using that key combo (ctrl-alt-f2 or f3 or f4 etc.) from there you can potentially roll back the driver, view system logs to troubleshoot, etc.
I had this happen the other day on mint as well, I just waited a few minutes till I thought it would be done and restarted (force power off). Everything was fine after that.