I got a new job and didn't tell my boss I'm pregnant

I was hired when I was 11weeks pregnant, with all the training and stuff like that I will be starting to actually work this next week I will be 18 weeks pregnant. I haven't told my boss (the owner). Who basically told me when I had a depression/anxiety attack one day while training "well you need to leave your personal issues at the door".

Basically I don't exactly want to tell her if that's how she responds to medical issues (my anxiety and depression is very much clinical) and honestly pregnancy feels a lot like a personal issue to me.

I feel really nervous and bad but do I have to tell her? I just want to keep it to myself (it doesn't affect my work I can preform all task and activities, I'm just a bit more emotional)