Plotting with dsolve for ODE

I have created a slope field, now I wish to overlay a single curve for the function that satisfies the equation. below is code so far.

clear

clc

[x,y] = meshgrid(-5:0.4:5,-5:0.4:5);

dydx = x.^2+y.^2-1;

L = sqrt(1+dydx.^2);

quiver(x,y,1./L,dydx./L,'k')

hold on

axis([-3 3 -3 3])

I have attempted to continue like this Unsucccessfuly:

syms y(x)

func = dsolve(diff(y,1) == x^2+y^2-1,y(0) == 0)

fplot(func,[-3 3])

Thank you for your assistance.