Anak, this is serious, please make sure you're following up closely with your pediatrician or go to the ER right away if baby's breathing gets worse, okay? Gasping and grunting need proper monitoring, hindi lang home care lang.
I know it's scary, pero the good news is your baby's doctor caught it and started treatment na. A few of us mums had babies on antibiotics and nebulizer before, recovery really depends on how severe the pneumonia is and how baby responds to the meds, so your doctor can give you a better timeline than me. Just keep giving the medicines on schedule, watch his breathing closely (especially when he plays), and don't skip any follow-up appointments. Strength, mama, you're doing great monitoring him!