Should I tell my Work?

I’m 4 weeks and 5 days, I usually would wait until I have had a scan before telling but I’m a community care worker (15 hour days) and they get me to do so much over time! So have like 1 or maybe 2 days a week off. Work is taking the life out of me now I’m pregnant and my job is difficult with moving and lifting etc (I work without a work partner to help). I’ve been so poorly over last 2 weeks and the office staff don’t seem to let me have time off ☹️ should I tell my boss while I’m still early on in pregnancy or stick it out?