These 2 days you’ve been producing colostrum so you can’t really feel it yet, but once the milk comes in, you can actually feel the milk going out of your breast when baby sucks:) especially during the let down reflex. It’s perfectly fine to top up with some FM for now if baby’s really hungry:) but also keep latching on demand.. your milk supply should come in within the next 2 days, and you might feel engorged, so keep latching.