self-intersection of plane nodal curves

Question

I'm trying to compute the self-intersection of a degree 5, 6-nodal, curve in $\mathbb{P}^2$, yet I've only done this computations for smooth curves and I'm not sure if the same procedure works when there are singularities. In other words, I'd like to know if given a degree $d$ singular curve in $\mathbb{P}^2$ then its cohomology class is still $dH$, where $H$ is the class of a line?