i have to find y' and y" using implicit differentiation

2x^3 - y^2 = 8

what i did was

d2x^3/dx - dy^2/dx = d8/dx

d2x^3/dx = 6x^2

dy^2/dx = 2y*y'

d8/dx = 0

6x^2 - 2yy' = 0

-6x^2=-2yy'

y'=6x^2/2y

= 3x^2 / y

but i don't know how to find 2nd derivative from here

how do i do it?