A duo is conclusive after 4 weeks so if that is what you used you should move on from hiv. Ask the clinic what test was used if you do not know.
Everyone gets flu and anyone can get Covid so hiv docs do not pay attention to symptoms and rely on hiv tests instead for hiv diagnosis, which you should do too.
You aren't infected with HIV. A 6 week's negative rules it out. Please keep following up with your GP for diagnosis of your ailment.