I can relate to your dilemna, welcome to the boards.
I lost a friendship early on. I was socially aware enough to not talk about any of my child's milestones. But, then I met someone who had a child of a similar age, and she was sooo interested in learning more about my DD and how she was reading at age 2 or so. Well, turns out, she really wasn't that interested or hearing about it bothered her, and the friendship abruptly ended.
Now I am even more careful. Luckily, there are gt communities all over. My closest friend here in town has a son who would have qualified for DYS easily, had she known about it, and recently when I was overwhelmed by achievement test results she was the only person whom I could talk to.
You'll figure it out. It is hard and you need support, you seem to have it in your in laws, our families don't really get it.