I have tested negative for the covid antigen rapid test, however i am displaying symptoms of covid- nasal congestion, loss of taste and smell. my brother was tested positive on 18 dec, and my wife (no symptoms) was in contact with him on the 15th ?

Repeat test with PCR: Rapid testing has been shown to be in accurate with a high numbers of false negative readings. Clinically it sounds like you have COVID-19 and I would repeat your testing with the PCR method. In the meantime I would quarantine until you were certain that you do not have COVID-19

COVID 19: Agree with earlier recommendation for PCR testing. If you are currently displaying symptoms that increases the likelihood of avoiding false negative results.