Enfamil - out of stock

My son is almost 10 months and he usually takes enfamil A+. I can't find this formula anywhere in my city anymore. I've tried to give him similac pro advance but he's been vomiting everyday, waking up crying and twisting, and has been pooping a lot. It's safe to assume this formula isn't agreeing with him. Does anyone have any recommendations of good formula to try? Even ones that are available online. My son doesn't have a milk protein allergy that I am aware of. Thanks!