anybody else's baby super fussy?

my son 9 weeks and he is super fussy dr put him on acid refulx meds and I give him gas meds cuz hes very gassy on the formula hes on he did just have shots on wed but hes been fussy before that like he will be fine forawhile then fussy rhen fine then fussy ect I told dr he didnt seem to concerned I also told him he likes to eat and eat he didn't seem to concered about that cuz he said hes not a chunky monkey so he said if it keeps up then to let me know