Textures for text,blocks,etc are extremely glitchy

Hey Mojang! Ive been playing MCWin10 for around 2 years now,and this has never happened to me,but: I joined the beta for MCPE 1.8 to test it out.When i actually got in the game,this appeared: I unenrolled from the beta,but it still glitched like this?? 

-Kosovar