Baby doesn’t like car rides

My son is almost 7 months and he hates being in his car seat. He cries until he vomits. I have to pull over to check if he has a dirty diaper, i feed him before we go anywhere too. We’re thinking of getting him a big boy carseat (convertible) but we honestly don’t think that’s the issue. Maybe he gets bored, crowded?? Do any of your babies went through a phase like this!