this household cant take a break

my kids just got over there colds now my son woke up throwing up everywhere twice... he said hes cold to and dont feel good... now im worryed... i still have coughing and mucus i cant get rid of. we tested for covid and flu last week it was neg... now only thing we been to was my bf nieces party saturday that was it noone else is sick... now im going catch whatever he has he was the one gave me a nasty head cold he caught at school that im on antibotics for that isnt doing much of any good... i know my daughter be next as well our immune systems are low. which we take vitamins everyday and extra vitamin c.