Am I right to be mad about not being acknowledged in a paper?

For context I spent 11 months working as a research assistant for a professor. I basically ran a user study for a post-doc's paper. I wasn't involved in designing the study but I was responding for advertising, collecting data, created and designed 200ish signals that were used for the study, all of which was a lot of painstaking effort.

The paper was recently published and I wasn't even acknowledged - the author thanked her parents and family. I know it doesn't matter at all but am I right to be pissed about this?