I'm 5 weeks pregnant and am a supervisor at a shop. It involves a lot of being on my feet, picking up some heavy objects, using a step ladder, confronting angry customers, serving people, bending down a lot, lifting shop shutters and other strenuous things. I'm not sure when to tell my manager as I feel I shouldn't be doing some of these things during early pregnancy but can't refuse to do them unless I tell them? I don't know if it's too early or not.