Anyone forced out?

I just found out that DH's parents are going to be around 2/23. They are coming to stay with his grandmother while his aunt and uncle go to visit their new grandchild. I am already starting to show so it will be really hard to hide in a month. I hate the idea of telling them b/c we have to rather then when we are ready. We had planned to tell family at 18 wks. 

The reason it is bothering me so much is that FIL will not keep it to himself. He'll tell everyone, which is not what we want at all. My IL's try but end up saying all the wrong things and with this topic there is a bad history with one of DH's sisters. Like she said evil things after Nicholas died and on our EDD in Nov called to say sorry but I am pg again. Ugg.

We haven't told anyone so far and did not tell people the last time. After our lost we told close family and a few friends. I feel like we should have that opinion again and it stinks that we may not. Maybe I will get lucky or let them think I gained some weight. Tell me it will be okay.