It happens every time I die in 18w44a. Whenever you die in survival or adventure mode it respawns you in your last location but all you can see is nothingness. It's like if you were to create a new world that had absolutely no blocks. I've waited for extended periods of time, tried destroying and placing blocks and even checked a few computer settings of mine but I'm not able to find the solution. I'm pretty sure it's a bug but I apologize if I'm the only one having this. Thank you for taking your time to read through this. I'd add a screenshot but whenever I try to screenshot it it only appears as a gray screen.