Formula

Similac or enfamil? My daughter was in similac but my son was put on enfamil from the hospital but it seems after a few bottles he gets really fussy and it seems he has a belly ache or something. Was thinking about putting him on what we had my daughter on because we went through the same thing with her we had to put her on a more gentle one. Once we switched her she was better. Should I totally switch brands or just find a more gentle one with the brand he’s on already?