Sometimes when I think about certain job that I have to do or some tasks, I will physically feel a rush of nauseous and dizziness to the point where I have to distract myself for it to go away. If I force myself through it, I would start to have some headache and conditions would get worse. 

It does not happen when I think about work in general but usually happens when I actually thinking about doing this work. Usually, these are tasks that I don't want to do but still, it should only upset me mentally but not giving any physical effect right? Anyone has this experience or know how to deal with it? I'm not even sure if this is anxiety or something else, please feel free to share your thoughts.