🚨⚠🚨⚠🚨⚠🚨⚠🚨⚠🚨⚠🚨⚠🚨⚠ EVERYONE I NEED ADVICE!!

Im feeling really sick and exhausted... Roman is exclusively breastfed (almost 4 months now) but I need a break today... Im feeling awful. His dad said he would take him for the day. But, I didnt pump any milk and I dont have the time to... So!!!: Can I give him Formula for the day? If so what is the best for an exclusively breastfed baby/preemie baby? Also, what kind of water do we use for the bottles??