My 4 month old has a sudden aversion to his car seat. Up until now, he would fall asleep almost immediately after we started driving. Now he starts crying as soon as we start driving, and won't stop. I'll pull over and nurse him for a few minutes until he unlatches and he's all smiles, then I put him back in, start driving and he starts screaming and crying again! I don't know what's wrong, he's had the same car seat since he was born. The straps aren't too tight, they're not bothering his neck. I'll even climb in the backseat with him while my SO drives and hold his hand and sing to him to try to comfort him, and he still won't stop crying. Is this normal? Just a phase that will pass? He's been fussy in general lately, I think he might be teething. I got him a raw Baltic amber necklace, so I hope that helps.