How do I tell my extreme & overly anxious mom i'm pregnant?

[Angelica]

Im 27, happily married, good job, nice home, AND 9 WEEKS PREGNANT =) I havnt even had my first ultrasound yet. My husband is very excited and he wants to tell the world. I am simply not ready nor do I want the attention. I compromised with him & let him tell his parents and his close friends w/ the acception that no one posts anthing to social media or tells my fam. The reason why im not ready to tell my fam specifically my mom is 1. Im only 9 wks. 2. My Mom, although I know she'll be thrilled she has always had severe anxiety problems & worries herself sick & constantly dreads the absolute worst (this is due to her graves disease) her anxiety & exrtremely intense behavior has always put extra unwanted stress on me. 3. My SIL has had 4 miscarriages. This was due to a disease. We accepted nature and knew a miscarriage was out of our control & just the inevitable because of her disease. Except for my mother, she took it all very very hard. She was very intense like "whoa, get a grip!!" Just picture Shirley MacLaine in "Terms of Endearment". My father and the rest of my family were fine. They know they can handle this type of thing. Im actually dying to tell my father & my GM but Im afraid they'd feel compelled to tell my mom. I had the idea of calling her on April Fools Day b/c i thought that would be a fun light hearted way to break it to her but at that point ill still only be 10 wks. Too soon? What is a good way to break it to my mom and when?