Am I being unreasonable?

My colleagues and I are working on a project. I was bought on because I’m always given shitty admin work to do. Now I have done all the work I have been assigned. My colleagues have not finished all of theirs.
During this project time I have been given another project I am running on my own. I was away for half a month and my colleagues want to dump some of their work onto me. Questioning what work I have and to depriortise my workload to help them. I told them NO! The work was divided up among us and we should aim to complete what we have been assigned. I have other workload and can only help when I have time.

Like WTF! I am even offended they asked me to stop what I am doing. Yes, I may be more junior than them but they are not my useless boss. Crazy people!