Jangan rasa bersalah, mama, kalau baby betul-betul ada symptoms macam sembelit, kembung, dan muntah, memang boleh tukar formula, tapi the key is to do it slowly and carefully so baby's tummy can adapt. A few of my mum friends went through the same thing, and kami semua agree that a week or two of transition (mixing the old and new formula gradually) works better than switching cold turkey, so the doctor might have meant give each formula a proper 1-2 week try with slow transition rather than jumping between brands so quickly. Since you've switched 4 times, maybe best to see your pediatrician again and work together on a proper transition plan for this new formula, they can also check if there's an underlying issue like lactose intolerance or cow's milk protein sensitivity that might need a special formula instead. You're doing your best for your baby, and that's what matters!