How to tell my husband?

It's killing me hiding my pregnancy from my husband! I just found out I was pregnant earlier this week, but I was trying to wait until I could think of the perfect way to tell him. I don't even think I can hide it for a week because I've been feeling very nauseated and sick lately so I know he's gonna question the way I've been acting sooner or later. His mom is supposed to be flying into this town next weekend to stay with us for a couple weeks so I dont know if I should wait until she comes to announce it to the whole immediate family because my mom was planning a big dinner for his mom and our family next Sunday,( if I can play off my sickness until then)or should I tell him now and we announce it together over dinner? Any other cute suggestions or announcing ideas? How did you announce??