Help preparing sd card checkingfor errors

[showmestuff-S2]

hhi I have an icon in notifications sayin preparing sd card checking for errors
my devic s3 mini runnin very slow
sometimes screen freeze
anybodys help wilo be greatly appreciated thanks in advance

 

[showmestuff-S2]

once the screen goes off the device is still on cuz wen I click the home button twice it makes noise
not much responds while it is active