help. 6 weeks old daughter has colds

my baby caught colds and has been suffering from it for a week now. she caught it from her cousin (5 years old, female) who (despite of asking not to) kept on coughing and sneezing in front of my child. I tried to keep her away from her cousin but the child kept on sticking with us until she finally caught her cold.

my baby's having a really hard time breathing now, and i'm super worried. I wanted to bring her to the doctor's but money's so tight rn. we only have enough for her diapers and milk. i'm on my wits end. can someone recommend a home remedy to treat colds and clogged nose? I'd really appreciate it. TYIA.