Work and pregnancy?! PLEASE REPLY

Ashleigh
Hey all, I'm 6+3 weeks today and I work in a very heavy truck part warehouse, so as soon as I found out two weeks ago I told my floor manager so he could put me on lighter duties (which he hasn't really?!) and his first reply was "was this planned" to which I replied yes and I got s bad reaction. I was told to go see the nurse who was also rude and told me "don't tell anyone because there's a high chance something could go wrong this early" -so encouraging- and she said I can't have a risk assesment until I get my green forms, so I've been having to lift extremely heavy things in and out of pallets all day everyday. 
Well today I got my papers through and my booking appt is 2 weeks today, can I inform HR now? And now I have the papers can the do a risk assesment even though I've not had my appt yet? 
So stressed and anxious I'm going to do harm!