Congratulations on your pregnancy! And I'm sorry you've had to go through your previous losses. It's devastating! We lost our 2nd last year just at the 14 week mark, after we had started telling people about the pregnancy and the issues we were having.
I know the common advice is to wait until your 2nd trimester until you say anything, in case things don't go as planned/hoped for. However, I'm of the mindset that if your close friends and family are supportive, they should be with you to share your joys and your sorrows, and support you. If they're the meddling sort, and will make more of a spectacle of any loss, then keep it private for you and your husband, and maybe 1 or 2 close friends. Especially with your 2.5 year old, you may NEED help for a few days after surgery if something goes wrong. In our case, I had a very easy D&C surgery after our miscarriage, but I was pretty sore for a day or 2 after, physically & emotionally. It was nice to have my best friend and my sister-in-law help with my 2 year old.
I'm assuming your fertility specialist may be looking at all possibilities about why you're miscarrying. In our case, we screened positive for Down Syndrome at 10 weeks, did a CVS at 12 weeks that confirmed it. During the CVS, the OB confirmed that the baby had significant malformations and would not survive. When we lost the baby 2 weeks later, at least we knew why. A CVS is similar to an amniocentesis, but looks at placenta cells and does earlier diagnostics for genetic issues.
We're now 36 weeks pregnant with a healthy baby girl. We did the same early CVS testing this time, just to rest assured that the genetic issues weren't systemic. We're both considered "older" at just over 35, so we were at increased risk.
I hope this helps, and that you're pregnancy goes well!