Can a baby just be "difficult"?

My baby is almost 7 months, pretty much since the day he was born he has been really difficult for me.. Everyone says Oh its just because you're a new mom! But I dont think its that anymore, or maybe Im doing something wrong.. He wants to be constantly moving around, wont ever sit in a swing or chair more than a few minutes, I dont mind holding him all day , but he is so squirmy I feel like Im going to drop him sometimes, but if I sit down while holding him he'll cry. He screams when we put him down even for a second, or if hes out of the house , like to go shopping if its longer than an hour or so he will have a meltdown in the car.. Im just so frustrated and exhausted. He takes a while to go to sleep but when he does he'll sleep pretty well.. Someone please tell me he will grow out of this, or its normal or SOMETHING .. I just feel like im messing up somewhere here