How to tell my work I'm pregnant

Desiree • Due with my rainbow baby Aug 6th Derik J McMurray
Okay so I'm extremely nervous about this. 
I'm an in home caregiver(CNA) and I don't see anyone but my clients. The last time I saw someone I worked with was at a meeting before I was even pregnant and that was over 20 weeks ago. I'm currently 19 weeks and 6 days and I read somewhere online that it's okay to wait until you're 20 weeks to let your boss know. Reasons I have waited this long is I had a previous miscarriage in August and I didn't want to share the news with them too soon because I was scared and then came the hours... They are terrible with giving me hours and I was just giving them another reason for them to stop giving me them. I have literally been begging them for hours for weeks now and I FINALLY got a whopping 12 more and they have been sending mass emails to everyone saying we need more people available for hours(SERIOUSLY?!?) So anyways in the first few weeks I was pregnant I called out ONCE! Because my morning sickness was so bad I couldn't get off the bathroom floor let alone get in my car and take care of someone else. I told them I just didn't feel good and boom! The harassment emails came in about them suppecting I was pregnant and that I was quitting! All I did was call and say I'm not feeling well today can I please have the day off. These women are so childish and act like we're in high school. I never responded to their rude emails and went on like it never happened because at the time it was no ones buissness but mine and my SO. My own family didn't even know yet. So with how they have been acting toward me and how I don't really have any type of work relationship with anyone I have no idea how the hell to them them i really am pregnant and no I don't need special treatment and yes I still want any and all hours you can give me until I can no longer work. 
I want it to be as professional as possible and in a way they don't have a reason to fire me or push me to quit. 😪 and yes I know I should get a new job but it's not so easy getting into a career while pregnant trust me I've tried.