Worried about getting fired because I’m pregnant

Guys.. I’m 13 weeks pregnant and I work for a super small employer as a marketing manager. They are super old school like the hired me as a work from home position but I’ve noticed they’ve started having expectations that I be there M-F 9-5 which I’ve been doing but taking a day here or there to work from home. I haven’t told them I’m pregnant yet because I’m afraid they will freak out 1 and 2 because really I’m barely far along enough to be in the safe zone. I’ve had multiple miscarriages. Like no one there has kids including the owner who’s wife is HR. She was never able to have kids which i have so so much sympathy for especially having been through my own struggles. Ever since I started showing (my bump has become almost unhidable) she’s started treating me differently I’m so afraid they are going to fire me. They’ve been super short, unforgiving of work from home days like they used to be and piling a lot on my plate, have been super verbally aggressive .. I’m not sure how to handle it. Yes I really need the job and I’m a hard worker.. I’ve never been fired in my life. I also generate a lot of revenue for them so all of it is just like yike anyone been through something similar?