Am I being stupid? Work

[Cmr1200]

I currently work as a door to door carer and do a few night sits here and there. My manager asked me to do a shadow shift today and a night shift after shadow with the same service user end of week. The young man that needed care smokes marijuana daily and smokes up to one joint every hour he is bedridden and smokes indoors.
I hadn't told my managers that I was preganant as it was so early and was waiting for my scan. When I left the shadow shift I was really at two minds whether I wanted to work the night sit as I would be there for 12 hours and inhaling second hand smoke. In the end I decided to tell my manager how I was pregnant and I was looking to hand in a written notice and I had to let them know I couldn't work with the service user as the smoke was a risk to my baby?
I don't want them thinking I'm some lunatic. Would you have reacted this way?

It's a bigger risk to you I think Op.

That seems sensible to me.

I would of been sleeping in a separate room. But may have inhaled smoke when checking in on service user in between the night, but I do think I made the right decision. Thankyou for your responses.

You did the right thing - no way would I sleep overnight in a smoky, marijuana-y home while pregnant. And they have an obligation to protect you and baby at work.