How to generate a random Normal distribution that variate slowly?

Question

I want to I want to generate a random Normal distribution that has a slow variation to imitate the slow-fading. I Use Matlab so I did this:

pd_lp = makedist('Normal','mu',2,'sigma',1);
R_lp_base = random(pd_lp,5000,1);
figure()
plot(R_lp_base)

This code only generates a normal distribution but the variation is rapid. So I have thought of generating a Normal distribution with less samples and Interpolate it like this:

pd_lp = makedist('Normal','mu',2,'sigma',1);
R_lp_base = random(pd_lp,50,1);
R_lp=interp1(1:50,R_lp_base,linspace(1,50,5000)','spline');
figure
plot(R_lp)

As you can see the "R_lp" is variating slowly but it does not follow a Normal distribution (verified through the K-S test : kstest(R_lp)).

Can anyone please help me to generate a Normal distibution with 5000 samples that variates slowly ?