Constant function given an inequality

Question

Let $f:\mathbb{R}\rightarrow\mathbb{R}$ that satisfies $f(x + y)\leq yf(x) + f(f(x))$ for all $x,y\in\mathbb{R}$. Show that $f(x)=0$ for all $x\leq0$.

I tried setting y = 0 in an attempt to prove it but i couldn't and there is nothing else