Ah mama, yan talaga ang common worry natin! Honestly, it's okay to mix breastmilk and formula, marami sa amin ang ginawa yan, lalo na kung parang hungry pa rin ang baby after nursing. The thing is, sometimes sa 2 months, babies just have growth spurts kaya mas gutom talaga, so it doesn't necessarily mean your milk supply is low, pero if you're concerned, best to check with your pedia or lactation consultant para ma-assess properly kung talagang kailangan ng mix or kung may adjustment lang na kailangan sa feeding routine. Don't stress yourself too much though, marami sa amin ang nag-combine and ang babies namin turned out great!