This is a t test for dependent, and I need to find the SSd

Low Light 45, 15, 75, 30, 57

Bright Light 49, 13, 82, 30, 60

Here is what I did WRONG:

I took the difference between these scores;

45-49=-4

15-13=2

75-82=-7

30-30=0

57-60=-3

the total was -12, and then I did my D^2 - (D)^2/N

-4^2+2^2+-7^2+-3^2 - (-4+2+-7+-3)^2/5

I do not know what I did wrong.