$(-1)^2$ in $\mathbb{Q}_p$

Question

In p-adic field $\mathbb{Q}_p$, $-1=\sum_{i=0}^{\infty}(p-1)p^i$, but when I take square of $-1$ $\mathbb{Q}_p$, I am getting $1+2p+3p^2...$. Shouldn't it be $1$ as we are squaring $-1$? The product that I used is the usual convolution. Am I doing something wrong?