Age 7- the age of demon child

My son turned 7 in December and the witching hour has not ceased.  It's like another child has inhabited him and taken over! I miss my sweet 6 year old that was good tempered and lighthearted.  Now I'm dealing with a stubborn, fidgety, demon child! It reminds me if when he was 2-3 years old and was such a pistol.  I remember thinking I could not handle it but he made it through and things got better.  So I'm writing this to remind myself that this to shall pass and one day I will forget about the hellish days of this 7 year old!