When should we stop lifting heavy things?

T

So I’m on week 7/8 and I work basically a labor job so I’m always lifting heavy things. I’m going to ask my doctor this when I get to my first appointment but does anyone know when you’re supposed to stop lifting heavy things and what the max you’re supposed to lift. Since I’m not really showing yet I haven’t told my job that I’m pregnant so no one really knows that I can’t lift heavy things. I try to watch out for most things and only lift things that are 30 pounds but when should I really start to be careful?