Affiliate Marketing Secrets

I have worked there for over 2 years. I’m scared that they will judge me, so I have held off on telling them. I am almost 5 months pregnant and it’s starting to become obvious that I’m gaining baby and not fat. I just had to call in and say that I couldn’t work tomorrow because I have a fever, my boss seems disappointed because I’ve always usually worked when I’m sick. I know if I call and explain to her that I am pregnant and this is my first time being sick with a fever since I’ve gotten pregnant, but I am scared that they will use that as an excuse to not give me as many hours. I am 18 and single, and my work place is religiously affiliated.
I guess what I’m asking is how I should tell my boss (over the phone) tonight when I call her.