Can try to use happy noz patches then help her to suck out the mucus (can use the sucker or just roll the tip of tissue then insert in to trigger the sneeze - works best for mine). If you’re worried, you can bring baby to PD, but most likely won’t be given any medications as they are still too young.
get sterimar baby and suck out the mucus. most likely baby is congested due to backflow when sleeping.