Hi, I told my work when I was 12wks, I didnt need to cos wasnt showing but I work in a school as well and to be honest I felt rough most of the time and so people were more relaxed around me an understood if I needed to sit down or go toilet. Also, im a teaching assistant so I didnt want to be climbing up ladders to do displays or breaking up fights, so it might be a good Idea to tell ur work for safety reasons espec if your worried, you dont have to tell everyone just maybe people you work directly with. hope everything goes well:)