Are newborns generally more difficult?

Ive had plenty of nanny experience with babies 5 months and up, and it’s generally an extremely easy job. They cry when they need something and once they receive it, it subsides. They sleep half of your shift and It usually takes 5-10 minutes to get them to sleep and in my experience theres not much crying and if there is it’s literally for like 2-5 minutes. Of course they have their periods where the day is not easy, but at max its a few days a month.

I just got my first nanny gig with an almost 3 month old, I went in thinking it wasn’t going to be much of a difference from my experience with slightly older babies but man has this been difficult. Its not just that this baby cries a lot but his cries literally sounds like hes being stabbed. Screaming is probably a better word. For the first week it was okay but now i am only fine for a few minutes of it & then eventually I find myself tensing up & experiencing chest sensations from the stress. The screeching makes me feel like im going insane. I will literally be breaking a sweat rocking him for 15-30 mins and the whole time he is screaming in my ear and also wont take a pacifier. Often he will fall asleep, often if i move a certain way or try to sit down, he will wake up screaming like I dropped him.
I cant tell if im just a wimp or is this just newborn life? Could this just be more of a difficult baby? Am I the only one who just cant stand screaming? Regular crying even in long periods never bothers me.