Need opinions.

So I just started my new job at a warehouse, packing boxes of garbage bags and putting them on pallets, not a very hard job but being 6 months pregnant is kinda tough on baby. Took myself to er last night because I started having pains in my abdomen. And it turns out I was having contractions, but my cervix was completely closed and baby was doing fine. So my question is should I continue to work there and tell them I need more frequent breaks and need to set more or should I find an easier job til after baby born.. I know it's a simple question and should be a simple answer but I got hired on without them knowing i was pregnant. And I don't want to lose the job by telling them I am.