Calander on iPad not showing data

When to look up Calander this moring ad it was blank and blank on all months, days etc I then went to setting to find it had been hidden ???? I had not selected this and no-one else has access to this ?? Since the last update Iso10 mysterious things have been happening like Siri starts looking up bizarre things with out being asked? It is as if Someone has gained access to my Apple products and playing tricks on me? I know except for apple this is hard to do but is apple doing this?