Unhappy baby

Anyone else have a generally unhappy baby? My son is 2months and 9 days old and he is my second. He is a very needy, fussy baby. I love him, I'm just worried there's something wrong. He was a late term premie and had complications. He has reflux but had been on meds for over a week. He is exclusively breastfed. I can't put him down without him crying. Other people usually can't hold him for long, if at all. He doesn't seem to smile voluntarily, He is overweight for his height.