16 week old and car rides (kinda long sorry)

Kat

Ok. So we took a 3 hour trip to the beach the other day and at first my son was like he usually was, just a bit fussy, but fell asleep pretty quickly. He woke up about 45 mins later and was crying so when my husband stopped to fill up I took him out and changed him then put him back in. Not too long after he started screaming and making choking sounds and then he spit up all the formula I had fed him. (Dummy me didn't pump before the trip, and yes he's had formula before). He pretty much cried the whole trip until we got about 45 mins away and we stopped again. I took him out and we walked around with him and then put him back in. He cried for a couple minutes and then fell asleep. On the way back he had 2 more episodes of screaming to the point of choking and the second one he threw up the bm I had fed him before buckling him in in hopes to make him fall asleep. Again we stopped and took him out, changed him and fed him again bc he was trying to latch. Noticed his bottom was red so I put diaper rash cream on it. He cried for a minute until I gave him his paci then he fell asleep for the rest of the 2 hour trip.

Anyone else had a kid suddenly hate the carseat to the point of screaming like this? He used to love the car and sleep or entertain himself but suddenly this trip was the worst. We were hoping to go from nc to fl in August but if he's like this for a 3 hour trip, I don't want to imagine a 10 hr one... This momma needs some help/ideas!