Hi! Normal lang yan, lalo na kung heavily formula feeding ka, breastfeeding talaga ang mas nakakadelay ng period kaya kung konti lang ang milk mo, it can still suppress menstruation a bit, pero formula feeding usually means periods come back faster than purely breastfed moms. That said, 5 months is still within the normal range, pero I'd suggest checking with your OB na lang para sure, especially kung may other symptoms ka or if you want peace of mind!