Traveling while pregnant

I just found out I'm pregnant 2 days ago and I think I'm about 4 weeks and I'm scheduled to go on a 2 week long vacation with my family (I'm 16) and I don't want to tell my mom I'm pregnant till after the vacation because I don't want to ruin everyone's good time. I'm a bit concerned about something going wrong especially because it's a 40 hour drive there and back and I get car sick so along with morning sickness I feel like it's going to be hell does anyone have any advice on road trips while pregnant or just in general what I should do? I really want to tell her but I know it will ruin the whole trip and we all really need this trip but if I'm throwing up the whole time it will be suspicious (please don't lecture me for being 16 and pregnant. I understand. I don't need you to tell me I made a mistake.)